cmd/relspec/prisma_options.go

@@ -10,17 +10,19 @@ func newReaderOptions(filePath, connString string) *readers.ReaderOptions {
 		FilePath:         filePath,
 		ConnectionString: connString,
 		Prisma7:          prisma7,
+		StrictDirectives: strictDirectives,
 	}
 }
 
 func newWriterOptions(outputPath, packageName string, flattenSchema bool, nullableTypes, nullableArrays string, continueOnError bool) *writers.WriterOptions {
 	return &writers.WriterOptions{
-		OutputPath:      outputPath,
+		OutputPath:       outputPath,
-		PackageName:     packageName,
+		PackageName:      packageName,
-		FlattenSchema:   flattenSchema,
+		FlattenSchema:    flattenSchema,
-		NullableTypes:   nullableTypes,
+		NullableTypes:    nullableTypes,
-		NullableArrays:  nullableArrays,
+		NullableArrays:   nullableArrays,
-		Prisma7:         prisma7,
+		Prisma7:          prisma7,
-		ContinueOnError: continueOnError,
+		ContinueOnError:  continueOnError,
+		StrictDirectives: strictDirectives,
 	}
 }

cmd/relspec/root.go

@@ -10,10 +10,11 @@ import (
 
 var (
 	// Version information, set via ldflags during build
-	version   = "dev"
+	version          = "dev"
-	buildDate = "unknown"
+	buildDate        = "unknown"
-	prisma7   bool
+	prisma7          bool
-	noVersion bool
+	noVersion        bool
+	strictDirectives bool
 )
 
 func init() {
@@ -72,6 +73,7 @@ func init() {
 	rootCmd.AddCommand(reportCmd)
 	rootCmd.PersistentFlags().BoolVar(&prisma7, "prisma7", false, "Use Prisma 7 generator conventions when reading/writing Prisma schemas")
 	rootCmd.PersistentFlags().BoolVar(&noVersion, "no-version", false, "Suppress the RelSpec version header")
+	rootCmd.PersistentFlags().BoolVar(&strictDirectives, "strict-directives", false, "Fail on unknown or untranslatable DBML dialect directives (@postgres:, @sqlite:, …)")
 }
 
 // printVersionHeader prints the "RelSpec <version> (built: <date>)" banner

docs/DBML_DIRECTIVES.md

@@ -0,0 +1,115 @@
+# DBML Dialect Directives
+
+DBML has no dialect-neutral way to express database-specific features such as
+PostgreSQL table partitioning or SQLite `WITHOUT ROWID`. RelSpec adds **dialect
+directives** — explicit, parseable lines embedded in a `.dbml` file that are:
+
+- stored losslessly in the intermediate model (under each object's `Metadata`),
+- preserved unchanged through a `DBML → model → DBML` round-trip,
+- translated to SQL **only** by the writer for the matching dialect
+  (`@postgres:` clauses appear in PostgreSQL output, never in SQLite output, and
+  vice-versa).
+
+## Grammar
+
+A directive is a single line, matched on its trimmed content:
+
+```
+@<namespace>[(<target>)]: <args>
+```
+
+| Part | Rules |
+|------|-------|
+| `namespace` | `^[a-z][a-z0-9_]*$` — e.g. `postgres`, `sqlite`. Future dialects allowed. |
+| `(target)` | Optional. A **column name** only, valid only on a directive line inside a table body. Bare or single/double quoted. |
+| `args` | Everything after the first `:`, trimmed. Otherwise preserved **verbatim**. Must be non-empty. |
+
+The **key** of a directive is derived: the lowercased first whitespace-delimited
+token of `args` (`partition by RANGE (created_at)` → `partition`). It drives
+duplicate detection and writer dispatch.
+
+## Location
+
+Where the line appears determines which object it attaches to:
+
+| Position in the file | Attaches to |
+|----------------------|-------------|
+| Before the first `Table {` | database (`db.Metadata`) |
+| Table body, no `(target)` | that table |
+| Table body, `(col)` target | column `col` of that table (error if `col` is unknown) |
+| Inside an `indexes { }` block | the **most recently listed** index entry in that block; `(target)` is not allowed |
+
+```dbml
+@postgres: search_path myapp          -- database
+
+Table myapp.events {
+  id bigint [pk]
+  created_at timestamp [not null]
+  @postgres(id): identity always      -- column "id"
+  @postgres: partition by RANGE (created_at)   -- table
+  @postgres: tablespace fast_data              -- table
+  @sqlite: without rowid                        -- table
+
+  indexes {
+    (created_at) [name: 'idx_events_created']
+    @postgres: with (fillfactor=90)   -- index "idx_events_created"
+    @postgres: tablespace idx_space    -- index "idx_events_created"
+  }
+}
+```
+
+## Duplicate policy
+
+- **Repeatable by default** — every directive with the same `(namespace, key)` at
+  one location is kept, in source order.
+- **Singletons** raise a line-numbered error on a second occurrence at the same
+  location. Current singletons: `postgres` `partition`, `tablespace`, `inherits`,
+  `storage`, `compression`, `identity`; `sqlite` `without`, `strict`, `collate`.
+
+## Strict mode
+
+CLI flag `--strict-directives` (also `ReaderOptions.StrictDirectives` /
+`WriterOptions.StrictDirectives`):
+
+- **Reader**: an unknown namespace or key is a hard error. Without strict mode it
+  is stored and preserved silently, and round-trips unchanged.
+- **PostgreSQL / SQLite writer**: a directive for **that** writer's own dialect
+  whose key it cannot translate is a hard error. Without strict mode, translatable
+  keys are emitted and the rest are skipped. Directives for other dialects are
+  always ignored, never emitted.
+
+## Errors
+
+All are line-numbered (`dbml: line N: …`):
+
+- no colon, or empty `args`
+- namespace empty or not matching `[a-z][a-z0-9_]*`
+- `(target)` naming an unknown column, or used at the top level / in an `indexes` block
+- a directive in the catalog used at a location it is not valid for
+- duplicate singleton at the same location
+- (strict mode) unknown `(namespace, key)`
+
+## Supported directive matrix
+
+### `@postgres`
+
+| Key | Locations | SQL emitted | Notes |
+|-----|-----------|-------------|-------|
+| `partition` | table | `PARTITION BY <args>` appended to `CREATE TABLE` | e.g. `@postgres: partition by RANGE (created_at)` |
+| `inherits` | table | `INHERITS (<args>)` — args verbatim | |
+| `with` | table, index | `WITH (<params>)` | On an index, wins over `WITH` derived from the index comment. `@postgres: with (fillfactor=90)` |
+| `tablespace` | table, index | `TABLESPACE <name>` | Emitted after `WITH`, before `WHERE` on indexes |
+| `storage` | column | `STORAGE <mode>` in the column definition | e.g. `@postgres(blob): storage external` |
+| `compression` | column | `COMPRESSION <method>` | |
+| `identity` | column | `identity always` → `GENERATED ALWAYS AS IDENTITY`; `identity default` / `identity by default` → `GENERATED BY DEFAULT AS IDENTITY` | |
+
+### `@sqlite`
+
+| Key | Locations | SQL emitted | Notes |
+|-----|-----------|-------------|-------|
+| `without` | table | `WITHOUT ROWID` table option | `@sqlite: without rowid` |
+| `strict` | table | `STRICT` table option | `WITHOUT ROWID` is emitted before `STRICT` |
+| `collate` | column | ` COLLATE <name>` in the column definition | e.g. `@sqlite(name): collate NOCASE` |
+
+Unknown namespaces and keys not in these tables are still preserved losslessly
+(and round-trip through the DBML writer) whenever strict mode is off.

pkg/models/directives.go

@@ -0,0 +1,237 @@
+package models
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// Directive is a dialect-specific instruction embedded in a source schema
+// (currently DBML) that is preserved losslessly in the intermediate model and
+// consumed only by the writer for its namespace. Directives are stored in the
+// Metadata map of the object they apply to, under DirectivesMetadataKey.
+//
+// Example DBML: `@postgres: partition by RANGE (created_at)` parses to
+// Directive{Namespace: "postgres", Key: "partition", Args: "partition by RANGE (created_at)"}.
+type Directive struct {
+	// Namespace is the dialect the directive targets, e.g. "postgres" or "sqlite".
+	Namespace string `json:"namespace" yaml:"namespace"`
+	// Key is the lowercased first token of Args, used for duplicate detection
+	// and writer dispatch.
+	Key string `json:"key,omitempty" yaml:"key,omitempty"`
+	// Args is the verbatim argument text following the "@namespace:" prefix.
+	Args string `json:"args" yaml:"args"`
+	// Line is the 1-based source line the directive was read from, when known.
+	Line int `json:"line,omitempty" yaml:"line,omitempty"`
+}
+
+// DirectivesMetadataKey is the Metadata map key under which the ordered list of
+// dialect directives for an object is stored.
+const DirectivesMetadataKey = "directives"
+
+// DirectiveKey derives the Key for a directive from its argument text: the
+// lowercased first whitespace-delimited token.
+func DirectiveKey(args string) string {
+	fields := strings.Fields(args)
+	if len(fields) == 0 {
+		return ""
+	}
+	return strings.ToLower(fields[0])
+}
+
+// AddDirective appends d to the directive list stored in meta. The caller is
+// responsible for ensuring meta is non-nil (all Init* constructors allocate it).
+// If d.Key is empty it is derived from d.Args.
+func AddDirective(meta map[string]any, d Directive) {
+	if meta == nil {
+		return
+	}
+	if d.Key == "" {
+		d.Key = DirectiveKey(d.Args)
+	}
+	existing := GetDirectives(meta)
+	existing = append(existing, d)
+	meta[DirectivesMetadataKey] = existing
+}
+
+// GetDirectives returns the directives stored in meta, sorted deterministically
+// by (Namespace, Line, Args). It tolerates both a freshly built []Directive and
+// the []any of map[string]any produced by a JSON/YAML round-trip.
+func GetDirectives(meta map[string]any) []Directive {
+	if meta == nil {
+		return nil
+	}
+	raw, ok := meta[DirectivesMetadataKey]
+	if !ok || raw == nil {
+		return nil
+	}
+
+	var out []Directive
+	switch v := raw.(type) {
+	case []Directive:
+		out = append(out, v...)
+	case []any:
+		for _, item := range v {
+			if d, ok := directiveFromAny(item); ok {
+				out = append(out, d)
+			}
+		}
+	}
+
+	sort.SliceStable(out, func(i, j int) bool {
+		if out[i].Namespace != out[j].Namespace {
+			return out[i].Namespace < out[j].Namespace
+		}
+		if out[i].Line != out[j].Line {
+			return out[i].Line < out[j].Line
+		}
+		return out[i].Args < out[j].Args
+	})
+	return out
+}
+
+// directiveFromAny decodes a single directive from the loosely typed forms that
+// survive a JSON or YAML round-trip (map[string]any / map[any]any).
+func directiveFromAny(item any) (Directive, bool) {
+	switch m := item.(type) {
+	case Directive:
+		return m, true
+	case map[string]any:
+		return directiveFromStringMap(m), true
+	case map[any]any:
+		sm := make(map[string]any, len(m))
+		for k, val := range m {
+			if ks, ok := k.(string); ok {
+				sm[ks] = val
+			}
+		}
+		return directiveFromStringMap(sm), true
+	}
+	return Directive{}, false
+}
+
+func directiveFromStringMap(m map[string]any) Directive {
+	d := Directive{}
+	if s, ok := m["namespace"].(string); ok {
+		d.Namespace = s
+	}
+	if s, ok := m["key"].(string); ok {
+		d.Key = s
+	}
+	if s, ok := m["args"].(string); ok {
+		d.Args = s
+	}
+	switch n := m["line"].(type) {
+	case int:
+		d.Line = n
+	case int64:
+		d.Line = int(n)
+	case float64:
+		d.Line = int(n)
+	}
+	if d.Key == "" {
+		d.Key = DirectiveKey(d.Args)
+	}
+	return d
+}
+
+// DirectivesForNamespace returns the directives in meta that target ns, in the
+// deterministic order of GetDirectives.
+func DirectivesForNamespace(meta map[string]any, ns string) []Directive {
+	all := GetDirectives(meta)
+	if len(all) == 0 {
+		return nil
+	}
+	out := make([]Directive, 0, len(all))
+	for _, d := range all {
+		if d.Namespace == ns {
+			out = append(out, d)
+		}
+	}
+	return out
+}
+
+// HasDirective reports whether meta contains a directive with the given
+// namespace and key.
+func HasDirective(meta map[string]any, ns, key string) bool {
+	for _, d := range GetDirectives(meta) {
+		if d.Namespace == ns && d.Key == key {
+			return true
+		}
+	}
+	return false
+}
+
+// DirectiveSpec describes a documented directive in the catalog.
+type DirectiveSpec struct {
+	// Singleton means only one directive with this namespace/key may appear at
+	// a single location; a second one is a parse error.
+	Singleton bool
+	// Locations lists the location kinds the directive is valid at
+	// ("database", "table", "column", "index").
+	Locations []string
+}
+
+// Location kinds a directive may attach to.
+const (
+	DirectiveLocationDatabase = "database"
+	DirectiveLocationTable    = "table"
+	DirectiveLocationColumn   = "column"
+	DirectiveLocationIndex    = "index"
+)
+
+// DirectiveCatalog is the set of documented directives per namespace. It is used
+// for strict-mode validation in readers and writers; unknown namespaces/keys are
+// still preserved losslessly when strict mode is off.
+var DirectiveCatalog = map[string]map[string]DirectiveSpec{
+	"postgres": {
+		"partition":   {Singleton: true, Locations: []string{DirectiveLocationTable}},
+		"tablespace":  {Singleton: true, Locations: []string{DirectiveLocationTable, DirectiveLocationIndex}},
+		"inherits":    {Singleton: true, Locations: []string{DirectiveLocationTable}},
+		"with":        {Singleton: false, Locations: []string{DirectiveLocationTable, DirectiveLocationIndex}},
+		"storage":     {Singleton: true, Locations: []string{DirectiveLocationColumn}},
+		"compression": {Singleton: true, Locations: []string{DirectiveLocationColumn}},
+		"identity":    {Singleton: true, Locations: []string{DirectiveLocationColumn}},
+	},
+	"sqlite": {
+		"without": {Singleton: true, Locations: []string{DirectiveLocationTable}},
+		"strict":  {Singleton: true, Locations: []string{DirectiveLocationTable}},
+		"collate": {Singleton: true, Locations: []string{DirectiveLocationColumn}},
+	},
+}
+
+// LookupDirectiveSpec returns the catalog spec for a namespace/key and whether
+// it is documented.
+func LookupDirectiveSpec(ns, key string) (DirectiveSpec, bool) {
+	keys, ok := DirectiveCatalog[ns]
+	if !ok {
+		return DirectiveSpec{}, false
+	}
+	spec, ok := keys[key]
+	return spec, ok
+}
+
+// DirectiveLocationAllowed reports whether a documented directive may appear at
+// the given location. Unknown directives (not in the catalog) are allowed
+// everywhere so they can be preserved.
+func DirectiveLocationAllowed(ns, key, location string) bool {
+	spec, ok := LookupDirectiveSpec(ns, key)
+	if !ok {
+		return true
+	}
+	for _, l := range spec.Locations {
+		if l == location {
+			return true
+		}
+	}
+	return false
+}
+
+// FormatDirectiveLine renders a directive back to its DBML source form, e.g.
+// "@postgres: partition by RANGE (created_at)" or "@postgres(id): identity always".
+func FormatDirectiveLine(d Directive, target string) string {
+	if target != "" {
+		return fmt.Sprintf("@%s(%s): %s", d.Namespace, target, d.Args)
+	}
+	return fmt.Sprintf("@%s: %s", d.Namespace, d.Args)
+}

pkg/models/directives_test.go

@@ -0,0 +1,133 @@
+package models
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestDirectiveKey(t *testing.T) {
+	cases := map[string]string{
+		"partition by RANGE (created_at)": "partition",
+		"WITHOUT ROWID":                   "without",
+		"  strict  ":                      "strict",
+		"":                                "",
+	}
+	for args, want := range cases {
+		if got := DirectiveKey(args); got != want {
+			t.Errorf("DirectiveKey(%q) = %q, want %q", args, got, want)
+		}
+	}
+}
+
+func TestAddDirectiveDerivesKey(t *testing.T) {
+	meta := map[string]any{}
+	AddDirective(meta, Directive{Namespace: "postgres", Args: "partition by RANGE (x)", Line: 2})
+	AddDirective(meta, Directive{Namespace: "postgres", Key: "tablespace", Args: "tablespace fast", Line: 3})
+
+	got := GetDirectives(meta)
+	if len(got) != 2 {
+		t.Fatalf("got %d directives, want 2", len(got))
+	}
+	if got[0].Key != "partition" {
+		t.Errorf("derived key = %q, want %q", got[0].Key, "partition")
+	}
+	if got[1].Key != "tablespace" {
+		t.Errorf("explicit key = %q, want %q", got[1].Key, "tablespace")
+	}
+}
+
+func TestAddDirectiveNilMeta(t *testing.T) {
+	// Must not panic.
+	AddDirective(nil, Directive{Namespace: "postgres", Args: "strict"})
+}
+
+func TestGetDirectivesOrdering(t *testing.T) {
+	meta := map[string]any{}
+	AddDirective(meta, Directive{Namespace: "sqlite", Args: "strict", Line: 9})
+	AddDirective(meta, Directive{Namespace: "postgres", Args: "with (b)", Line: 5})
+	AddDirective(meta, Directive{Namespace: "postgres", Args: "with (a)", Line: 5})
+	AddDirective(meta, Directive{Namespace: "postgres", Args: "partition by x", Line: 2})
+
+	got := GetDirectives(meta)
+	wantArgs := []string{"partition by x", "with (a)", "with (b)", "strict"}
+	if len(got) != len(wantArgs) {
+		t.Fatalf("got %d directives, want %d", len(got), len(wantArgs))
+	}
+	for i, w := range wantArgs {
+		if got[i].Args != w {
+			t.Errorf("directive[%d].Args = %q, want %q", i, got[i].Args, w)
+		}
+	}
+}
+
+func TestGetDirectivesTolerantDecodeAfterJSON(t *testing.T) {
+	meta := map[string]any{}
+	AddDirective(meta, Directive{Namespace: "postgres", Args: "partition by RANGE (created_at)", Line: 4})
+	AddDirective(meta, Directive{Namespace: "sqlite", Args: "without rowid", Line: 6})
+
+	blob, err := json.Marshal(meta)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	var round map[string]any
+	if err := json.Unmarshal(blob, &round); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+
+	got := GetDirectives(round)
+	if len(got) != 2 {
+		t.Fatalf("got %d directives after JSON round-trip, want 2", len(got))
+	}
+	if got[0].Namespace != "postgres" || got[0].Key != "partition" || got[0].Line != 4 {
+		t.Errorf("post-JSON directive[0] = %+v", got[0])
+	}
+	if got[0].Args != "partition by RANGE (created_at)" {
+		t.Errorf("post-JSON args not verbatim: %q", got[0].Args)
+	}
+	if got[1].Namespace != "sqlite" || got[1].Key != "without" {
+		t.Errorf("post-JSON directive[1] = %+v", got[1])
+	}
+}
+
+func TestDirectivesForNamespaceAndHasDirective(t *testing.T) {
+	meta := map[string]any{}
+	AddDirective(meta, Directive{Namespace: "postgres", Args: "partition by x", Line: 1})
+	AddDirective(meta, Directive{Namespace: "sqlite", Args: "strict", Line: 2})
+
+	pg := DirectivesForNamespace(meta, "postgres")
+	if len(pg) != 1 || pg[0].Key != "partition" {
+		t.Errorf("DirectivesForNamespace(postgres) = %+v", pg)
+	}
+	if !HasDirective(meta, "sqlite", "strict") {
+		t.Error("HasDirective(sqlite, strict) = false, want true")
+	}
+	if HasDirective(meta, "postgres", "tablespace") {
+		t.Error("HasDirective(postgres, tablespace) = true, want false")
+	}
+}
+
+func TestDirectiveLocationAllowed(t *testing.T) {
+	if !DirectiveLocationAllowed("postgres", "partition", DirectiveLocationTable) {
+		t.Error("partition should be allowed at table level")
+	}
+	if DirectiveLocationAllowed("postgres", "partition", DirectiveLocationColumn) {
+		t.Error("partition should not be allowed at column level")
+	}
+	// Unknown directives are allowed everywhere so they can be preserved.
+	if !DirectiveLocationAllowed("postgres", "bogus", DirectiveLocationDatabase) {
+		t.Error("unknown key should be allowed everywhere")
+	}
+	if !DirectiveLocationAllowed("madeup", "x", DirectiveLocationTable) {
+		t.Error("unknown namespace should be allowed everywhere")
+	}
+}
+
+func TestFormatDirectiveLine(t *testing.T) {
+	d := Directive{Namespace: "postgres", Key: "identity", Args: "identity always"}
+	if got := FormatDirectiveLine(d, ""); got != "@postgres: identity always" {
+		t.Errorf("FormatDirectiveLine no target = %q", got)
+	}
+	if got := FormatDirectiveLine(d, "id"); got != "@postgres(id): identity always" {
+		t.Errorf("FormatDirectiveLine with target = %q", got)
+	}
+}

pkg/models/models.go

@@ -24,16 +24,17 @@ const (
 
 // Database represents the complete database schema
 type Database struct {
-	Name            string       `json:"name" yaml:"name"`
+	Name            string         `json:"name" yaml:"name"`
-	Description     string       `json:"description,omitempty" yaml:"description,omitempty" xml:"description,omitempty"`
+	Description     string         `json:"description,omitempty" yaml:"description,omitempty" xml:"description,omitempty"`
-	Schemas         []*Schema    `json:"schemas" yaml:"schemas" xml:"schemas"`
+	Schemas         []*Schema      `json:"schemas" yaml:"schemas" xml:"schemas"`
-	Domains         []*Domain    `json:"domains,omitempty" yaml:"domains,omitempty" xml:"domains,omitempty"`
+	Domains         []*Domain      `json:"domains,omitempty" yaml:"domains,omitempty" xml:"domains,omitempty"`
-	Comment         string       `json:"comment,omitempty" yaml:"comment,omitempty" xml:"comment,omitempty"`
+	Comment         string         `json:"comment,omitempty" yaml:"comment,omitempty" xml:"comment,omitempty"`
-	DatabaseType    DatabaseType `json:"database_type,omitempty" yaml:"database_type,omitempty" xml:"database_type,omitempty"`
+	DatabaseType    DatabaseType   `json:"database_type,omitempty" yaml:"database_type,omitempty" xml:"database_type,omitempty"`
-	DatabaseVersion string       `json:"database_version,omitempty" yaml:"database_version,omitempty" xml:"database_version,omitempty"`
+	DatabaseVersion string         `json:"database_version,omitempty" yaml:"database_version,omitempty" xml:"database_version,omitempty"`
-	SourceFormat    string       `json:"source_format,omitempty" yaml:"source_format,omitempty" xml:"source_format,omitempty"` // Source Format of the database.
+	SourceFormat    string         `json:"source_format,omitempty" yaml:"source_format,omitempty" xml:"source_format,omitempty"` // Source Format of the database.
-	UpdatedAt       string       `json:"updatedat,omitempty" yaml:"updatedat,omitempty" xml:"updatedat,omitempty"`
+	Metadata        map[string]any `json:"metadata,omitempty" yaml:"metadata,omitempty" xml:"-"`
-	GUID            string       `json:"guid" yaml:"guid" xml:"guid"`
+	UpdatedAt       string         `json:"updatedat,omitempty" yaml:"updatedat,omitempty" xml:"updatedat,omitempty"`
+	GUID            string         `json:"guid" yaml:"guid" xml:"guid"`
 }
 
 // SQLName returns the database name in lowercase for SQL compatibility.
@@ -226,22 +227,23 @@ func (d *Sequence) SQLName() string {
 
 // Column represents a table column
 type Column struct {
-	Name          string `json:"name" yaml:"name" xml:"name"`
+	Name          string         `json:"name" yaml:"name" xml:"name"`
-	Description   string `json:"description,omitempty" yaml:"description,omitempty" xml:"description,omitempty"`
+	Description   string         `json:"description,omitempty" yaml:"description,omitempty" xml:"description,omitempty"`
-	Table         string `json:"table" yaml:"table" xml:"table"`
+	Table         string         `json:"table" yaml:"table" xml:"table"`
-	Schema        string `json:"schema" yaml:"schema" xml:"schema"`
+	Schema        string         `json:"schema" yaml:"schema" xml:"schema"`
-	Type          string `json:"type" yaml:"type" xml:"type"`
+	Type          string         `json:"type" yaml:"type" xml:"type"`
-	Length        int    `json:"length,omitempty" yaml:"length,omitempty" xml:"length,omitempty"`
+	Length        int            `json:"length,omitempty" yaml:"length,omitempty" xml:"length,omitempty"`
-	Precision     int    `json:"precision,omitempty" yaml:"precision,omitempty" xml:"precision,omitempty"`
+	Precision     int            `json:"precision,omitempty" yaml:"precision,omitempty" xml:"precision,omitempty"`
-	Scale         int    `json:"scale,omitempty" yaml:"scale,omitempty" xml:"scale,omitempty"`
+	Scale         int            `json:"scale,omitempty" yaml:"scale,omitempty" xml:"scale,omitempty"`
-	NotNull       bool   `json:"not_null" yaml:"not_null" xml:"not_null"`
+	NotNull       bool           `json:"not_null" yaml:"not_null" xml:"not_null"`
-	Default       any    `json:"default,omitempty" yaml:"default,omitempty" xml:"default,omitempty"`
+	Default       any            `json:"default,omitempty" yaml:"default,omitempty" xml:"default,omitempty"`
-	AutoIncrement bool   `json:"auto_increment" yaml:"auto_increment" xml:"auto_increment"`
+	AutoIncrement bool           `json:"auto_increment" yaml:"auto_increment" xml:"auto_increment"`
-	IsPrimaryKey  bool   `json:"is_primary_key" yaml:"is_primary_key" xml:"is_primary_key"`
+	IsPrimaryKey  bool           `json:"is_primary_key" yaml:"is_primary_key" xml:"is_primary_key"`
-	Comment       string `json:"comment,omitempty" yaml:"comment,omitempty" xml:"comment,omitempty"`
+	Comment       string         `json:"comment,omitempty" yaml:"comment,omitempty" xml:"comment,omitempty"`
-	Collation     string `json:"collation,omitempty" yaml:"collation,omitempty" xml:"collation,omitempty"`
+	Collation     string         `json:"collation,omitempty" yaml:"collation,omitempty" xml:"collation,omitempty"`
-	Sequence      uint   `json:"sequence,omitempty" yaml:"sequence,omitempty" xml:"sequence,omitempty"`
+	Metadata      map[string]any `json:"metadata,omitempty" yaml:"metadata,omitempty" xml:"-"`
-	GUID          string `json:"guid" yaml:"guid" xml:"guid"`
+	Sequence      uint           `json:"sequence,omitempty" yaml:"sequence,omitempty" xml:"sequence,omitempty"`
+	GUID          string         `json:"guid" yaml:"guid" xml:"guid"`
 }
 
 // SQLName returns the column name in lowercase for SQL compatibility.
@@ -252,19 +254,20 @@ func (d *Column) SQLName() string {
 // Index represents a database index for optimizing query performance.
 // Indexes can be unique, partial, or include additional columns.
 type Index struct {
-	Name        string   `json:"name" yaml:"name" xml:"name"`
+	Name        string         `json:"name" yaml:"name" xml:"name"`
-	Description string   `json:"description,omitempty" yaml:"description,omitempty" xml:"description,omitempty"`
+	Description string         `json:"description,omitempty" yaml:"description,omitempty" xml:"description,omitempty"`
-	Table       string   `json:"table,omitempty" yaml:"table,omitempty" xml:"table,omitempty"`
+	Table       string         `json:"table,omitempty" yaml:"table,omitempty" xml:"table,omitempty"`
-	Schema      string   `json:"schema,omitempty" yaml:"schema,omitempty" xml:"schema,omitempty"`
+	Schema      string         `json:"schema,omitempty" yaml:"schema,omitempty" xml:"schema,omitempty"`
-	Columns     []string `json:"columns" yaml:"columns" xml:"columns"`
+	Columns     []string       `json:"columns" yaml:"columns" xml:"columns"`
-	Unique      bool     `json:"unique" yaml:"unique" xml:"unique"`
+	Unique      bool           `json:"unique" yaml:"unique" xml:"unique"`
-	Type        string   `json:"type" yaml:"type" xml:"type"`                                  // btree, hash, gin, gist, etc.
+	Type        string         `json:"type" yaml:"type" xml:"type"`                                  // btree, hash, gin, gist, etc.
-	Where       string   `json:"where,omitempty" yaml:"where,omitempty" xml:"where,omitempty"` // partial index condition
+	Where       string         `json:"where,omitempty" yaml:"where,omitempty" xml:"where,omitempty"` // partial index condition
-	Concurrent  bool     `json:"concurrent,omitempty" yaml:"concurrent,omitempty" xml:"concurrent,omitempty"`
+	Concurrent  bool           `json:"concurrent,omitempty" yaml:"concurrent,omitempty" xml:"concurrent,omitempty"`
-	Include     []string `json:"include,omitempty" yaml:"include,omitempty" xml:"include,omitempty"` // INCLUDE columns
+	Include     []string       `json:"include,omitempty" yaml:"include,omitempty" xml:"include,omitempty"` // INCLUDE columns
-	Comment     string   `json:"comment,omitempty" yaml:"comment,omitempty" xml:"comment,omitempty"`
+	Comment     string         `json:"comment,omitempty" yaml:"comment,omitempty" xml:"comment,omitempty"`
-	Sequence    uint     `json:"sequence,omitempty" yaml:"sequence,omitempty" xml:"sequence,omitempty"`
+	Metadata    map[string]any `json:"metadata,omitempty" yaml:"metadata,omitempty" xml:"-"`
-	GUID        string   `json:"guid" yaml:"guid" xml:"guid"`
+	Sequence    uint           `json:"sequence,omitempty" yaml:"sequence,omitempty" xml:"sequence,omitempty"`
+	GUID        string         `json:"guid" yaml:"guid" xml:"guid"`
 }
 
 // SQLName returns the index name in lowercase for SQL compatibility.
@@ -393,10 +396,11 @@ func (d *Script) SQLName() string {
 // InitDatabase initializes a new Database with empty slices
 func InitDatabase(name string) *Database {
 	return &Database{
-		Name:    name,
+		Name:     name,
-		Schemas: make([]*Schema, 0),
+		Schemas:  make([]*Schema, 0),
-		Domains: make([]*Domain, 0),
+		Domains:  make([]*Domain, 0),
-		GUID:    uuid.New().String(),
+		Metadata: make(map[string]any),
+		GUID:     uuid.New().String(),
 	}
 }
 
@@ -431,22 +435,24 @@ func InitTable(name, schema string) *Table {
 // InitColumn initializes a new Column
 func InitColumn(name, table, schema string) *Column {
 	return &Column{
-		Name:   name,
+		Name:     name,
-		Table:  table,
+		Table:    table,
-		Schema: schema,
+		Schema:   schema,
-		GUID:   uuid.New().String(),
+		Metadata: make(map[string]any),
+		GUID:     uuid.New().String(),
 	}
 }
 
 // InitIndex initializes a new Index with empty slices
 func InitIndex(name, table, schema string) *Index {
 	return &Index{
-		Name:    name,
+		Name:     name,
-		Table:   table,
+		Table:    table,
-		Schema:  schema,
+		Schema:   schema,
-		Columns: make([]string, 0),
+		Columns:  make([]string, 0),
-		Include: make([]string, 0),
+		Include:  make([]string, 0),
-		GUID:    uuid.New().String(),
+		Metadata: make(map[string]any),
+		GUID:     uuid.New().String(),
 	}
 }
 

pkg/readers/dbml/README.md

@@ -93,6 +93,50 @@ Ref: posts.user_id > users.id [delete: cascade]
 - Indexes and composite indexes
 - Table notes and column notes
 - Enums
+- Dialect directives (`@postgres:` / `@sqlite:` — see below)
+
+## Dialect directives
+
+Lines of the form `@<namespace>[(<column>)]: <args>` embed database-specific
+features that plain DBML cannot express (partitioning, `WITHOUT ROWID`,
+tablespaces, index storage parameters, …). They are stored losslessly on the
+relevant object's `Metadata` and round-trip unchanged through the DBML writer;
+the PostgreSQL and SQLite writers translate the ones they understand to SQL.
+
+```dbml
+@postgres: search_path myapp
+
+Table myapp.events {
+  id bigint [pk]
+  created_at timestamp [not null]
+  @postgres(id): identity always
+  @postgres: partition by RANGE (created_at)
+  @sqlite: without rowid
+
+  indexes {
+    (created_at) [name: 'idx_events_created']
+    @postgres: with (fillfactor=90)
+  }
+}
+```
+
+| Position | Attaches to |
+|----------|-------------|
+| Before the first `Table {` | database |
+| Table body, no `(target)` | that table |
+| Table body, `(col)` target | column `col` (error if unknown) |
+| Inside `indexes { }` | the most recently listed index entry |
+
+`args` is preserved verbatim; the **key** (lowercased first token) drives
+duplicate detection. Repeated directives are kept in order; catalog "singleton"
+keys error on a second occurrence at the same location. All errors are
+line-numbered.
+
+`ReaderOptions.StrictDirectives` (CLI `--strict-directives`) turns an unknown
+namespace or key into an error instead of preserving it silently.
+
+See [`docs/DBML_DIRECTIVES.md`](../../../docs/DBML_DIRECTIVES.md) for the full
+grammar and the supported-directive matrix.
 
 ## Notes
 

pkg/readers/dbml/directives.go

@@ -0,0 +1,137 @@
+package dbml
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// directiveLineRegex matches a dialect directive line:
+//
+//	@postgres: partition by RANGE (created_at)
+//	@postgres(id): identity always
+//
+// Group 1 is the namespace, group 2 the optional (column) target, group 3 the
+// raw argument text (validated separately so error messages can be specific).
+var directiveLineRegex = regexp.MustCompile(`^@([^():]*)(?:\(([^()]*)\))?\s*:(.*)$`)
+
+// namespaceRegex is the grammar for a directive namespace.
+var namespaceRegex = regexp.MustCompile(`^[a-z][a-z0-9_]*$`)
+
+// parsedDirective is a directive line that has been parsed but not yet attached
+// to a model object.
+type parsedDirective struct {
+	namespace string
+	target    string // column name; "" when absent
+	args      string
+	line      int
+}
+
+// parseDirectiveLine parses a single "@namespace[(target)]: args" line.
+func parseDirectiveLine(line string, lineNo int) (parsedDirective, error) {
+	m := directiveLineRegex.FindStringSubmatch(line)
+	if m == nil {
+		return parsedDirective{}, fmt.Errorf(
+			"dbml: line %d: malformed directive %q (expected \"@namespace: args\")", lineNo, line)
+	}
+
+	ns := strings.TrimSpace(m[1])
+	target := strings.TrimSpace(m[2])
+	args := strings.TrimSpace(m[3])
+
+	if !namespaceRegex.MatchString(ns) {
+		return parsedDirective{}, fmt.Errorf(
+			"dbml: line %d: invalid directive namespace %q (must match [a-z][a-z0-9_]*)", lineNo, ns)
+	}
+	if args == "" {
+		return parsedDirective{}, fmt.Errorf("dbml: line %d: directive @%s has no arguments", lineNo, ns)
+	}
+	if target != "" {
+		target = stripQuotes(target)
+	}
+
+	return parsedDirective{namespace: ns, target: target, args: args, line: lineNo}, nil
+}
+
+// attachDirective resolves the target model object from the current parser state
+// and stores the directive in its Metadata, enforcing location, duplicate and
+// strict-mode rules.
+func (r *Reader) attachDirective(
+	pd parsedDirective,
+	db *models.Database,
+	table *models.Table,
+	inTable, inIndexes bool,
+	lastIndex *models.Index,
+) error {
+	strict := r.options != nil && r.options.StrictDirectives
+	key := models.DirectiveKey(pd.args)
+
+	var meta map[string]any
+	var location string
+
+	switch {
+	case inIndexes:
+		if pd.target != "" {
+			return fmt.Errorf("dbml: line %d: directive target (%s) is not allowed inside an indexes block", pd.line, pd.target)
+		}
+		if lastIndex == nil {
+			return fmt.Errorf("dbml: line %d: directive @%s must follow an index definition", pd.line, pd.namespace)
+		}
+		if lastIndex.Metadata == nil {
+			lastIndex.Metadata = make(map[string]any)
+		}
+		meta = lastIndex.Metadata
+		location = models.DirectiveLocationIndex
+
+	case inTable && table != nil:
+		if pd.target != "" {
+			col, ok := table.Columns[pd.target]
+			if !ok {
+				return fmt.Errorf("dbml: line %d: directive target column %q not found in table %q", pd.line, pd.target, table.Name)
+			}
+			if col.Metadata == nil {
+				col.Metadata = make(map[string]any)
+			}
+			meta = col.Metadata
+			location = models.DirectiveLocationColumn
+		} else {
+			if table.Metadata == nil {
+				table.Metadata = make(map[string]any)
+			}
+			meta = table.Metadata
+			location = models.DirectiveLocationTable
+		}
+
+	default:
+		if pd.target != "" {
+			return fmt.Errorf("dbml: line %d: directive target (%s) is only valid inside a table", pd.line, pd.target)
+		}
+		if db.Metadata == nil {
+			db.Metadata = make(map[string]any)
+		}
+		meta = db.Metadata
+		location = models.DirectiveLocationDatabase
+	}
+
+	spec, documented := models.LookupDirectiveSpec(pd.namespace, key)
+
+	if strict && !documented {
+		return fmt.Errorf("dbml: line %d: unknown directive @%s: %s (strict mode)", pd.line, pd.namespace, key)
+	}
+	if documented && !models.DirectiveLocationAllowed(pd.namespace, key, location) {
+		return fmt.Errorf("dbml: line %d: directive @%s: %s is not valid at %s level", pd.line, pd.namespace, key, location)
+	}
+	if documented && spec.Singleton && models.HasDirective(meta, pd.namespace, key) {
+		return fmt.Errorf("dbml: line %d: duplicate @%s directive %q at %s level", pd.line, pd.namespace, key, location)
+	}
+
+	models.AddDirective(meta, models.Directive{
+		Namespace: pd.namespace,
+		Key:       key,
+		Args:      pd.args,
+		Line:      pd.line,
+	})
+	return nil
+}

pkg/readers/dbml/directives_test.go

@@ -0,0 +1,181 @@
+package dbml
+
+import (
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+)
+
+func parse(t *testing.T, strict bool, src string) (*models.Database, error) {
+	t.Helper()
+	r := NewReader(&readers.ReaderOptions{StrictDirectives: strict})
+	return r.parseDBML(src)
+}
+
+func firstTable(t *testing.T, db *models.Database) *models.Table {
+	t.Helper()
+	if len(db.Schemas) == 0 || len(db.Schemas[0].Tables) == 0 {
+		t.Fatal("no table parsed")
+	}
+	return db.Schemas[0].Tables[0]
+}
+
+func TestDirectives_AttachAtEachLocation(t *testing.T) {
+	src := `@postgres: search_path myapp
+
+Table myapp.events {
+  id bigint [pk]
+  created_at timestamp [not null]
+  @postgres(id): identity always
+  @postgres: partition by RANGE (created_at)
+
+  indexes {
+    (created_at) [name: 'idx_events_created']
+    @postgres: with (fillfactor=90)
+  }
+}
+`
+	db, err := parse(t, false, src)
+	if err != nil {
+		t.Fatalf("parse: %v", err)
+	}
+
+	if !models.HasDirective(db.Metadata, "postgres", "search_path") {
+		t.Errorf("database-level directive missing: %+v", db.Metadata)
+	}
+
+	tbl := firstTable(t, db)
+	if !models.HasDirective(tbl.Metadata, "postgres", "partition") {
+		t.Errorf("table-level directive missing: %+v", tbl.Metadata)
+	}
+
+	col := tbl.Columns["id"]
+	if col == nil || !models.HasDirective(col.Metadata, "postgres", "identity") {
+		t.Errorf("column-level directive missing")
+	}
+	// Verbatim args preserved.
+	if d := models.DirectivesForNamespace(col.Metadata, "postgres"); len(d) != 1 || d[0].Args != "identity always" {
+		t.Errorf("column directive args = %+v", d)
+	}
+
+	var idx *models.Index
+	for _, i := range tbl.Indexes {
+		idx = i
+	}
+	if idx == nil || !models.HasDirective(idx.Metadata, "postgres", "with") {
+		t.Errorf("index-level directive missing: %+v", idx)
+	}
+}
+
+func TestDirectives_RepeatablePreservedAndOrdered(t *testing.T) {
+	src := `Table s.t {
+  id int [pk]
+  @postgres: with (fillfactor=90)
+  @postgres: with (autovacuum_enabled=off)
+}
+`
+	db, err := parse(t, false, src)
+	if err != nil {
+		t.Fatalf("parse: %v", err)
+	}
+	tbl := firstTable(t, db)
+	got := models.DirectivesForNamespace(tbl.Metadata, "postgres")
+	if len(got) != 2 {
+		t.Fatalf("got %d directives, want 2", len(got))
+	}
+	if got[0].Args != "with (fillfactor=90)" || got[1].Args != "with (autovacuum_enabled=off)" {
+		t.Errorf("repeatable directives out of order: %+v", got)
+	}
+}
+
+func TestDirectives_SingletonDuplicateErrors(t *testing.T) {
+	src := `Table s.t {
+  id int [pk]
+  @postgres: partition by RANGE (a)
+  @postgres: partition by LIST (b)
+}
+`
+	_, err := parse(t, false, src)
+	if err == nil || !strings.Contains(err.Error(), "duplicate") {
+		t.Fatalf("want duplicate error, got %v", err)
+	}
+	if !strings.Contains(err.Error(), "line 4") {
+		t.Errorf("error not line-numbered: %v", err)
+	}
+}
+
+func TestDirectives_MalformedErrors(t *testing.T) {
+	cases := map[string]string{
+		"no colon":       "@postgres partition by x",
+		"empty args":     "@postgres:",
+		"bad namespace":  "@Postgres: partition by x",
+		"numeric prefix": "@1x: foo",
+	}
+	for name, line := range cases {
+		t.Run(name, func(t *testing.T) {
+			src := "Table s.t {\n  id int [pk]\n  " + line + "\n}\n"
+			_, err := parse(t, false, src)
+			if err == nil {
+				t.Fatalf("want error for %q", line)
+			}
+			if !strings.Contains(err.Error(), "line 3") {
+				t.Errorf("error not line-numbered: %v", err)
+			}
+		})
+	}
+}
+
+func TestDirectives_UnknownPreservedNonStrict(t *testing.T) {
+	src := `Table s.t {
+  id int [pk]
+  @postgres: frobnicate all the things
+  @clickhouse: engine MergeTree
+}
+`
+	db, err := parse(t, false, src)
+	if err != nil {
+		t.Fatalf("parse: %v", err)
+	}
+	tbl := firstTable(t, db)
+	if !models.HasDirective(tbl.Metadata, "postgres", "frobnicate") {
+		t.Error("unknown postgres key not preserved")
+	}
+	if !models.HasDirective(tbl.Metadata, "clickhouse", "engine") {
+		t.Error("unknown namespace not preserved")
+	}
+}
+
+func TestDirectives_StrictErrors(t *testing.T) {
+	src := `Table s.t {
+  id int [pk]
+  @postgres: frobnicate x
+}
+`
+	_, err := parse(t, true, src)
+	if err == nil || !strings.Contains(err.Error(), "strict mode") {
+		t.Fatalf("want strict-mode error, got %v", err)
+	}
+}
+
+func TestDirectives_UnknownColumnTargetErrors(t *testing.T) {
+	src := `Table s.t {
+  id int [pk]
+  @postgres(missing): identity always
+}
+`
+	_, err := parse(t, false, src)
+	if err == nil || !strings.Contains(err.Error(), "not found") {
+		t.Fatalf("want unknown-column error, got %v", err)
+	}
+}
+
+func TestDirectives_WrongLocationErrors(t *testing.T) {
+	// partition is table-only.
+	src := "@postgres: partition by RANGE (x)\n\nTable s.t {\n  id int [pk]\n}\n"
+	_, err := parse(t, false, src)
+	if err == nil || !strings.Contains(err.Error(), "not valid at database level") {
+		t.Fatalf("want location error, got %v", err)
+	}
+}

pkg/readers/dbml/reader.go

@@ -435,11 +435,14 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 	var inIndexes bool
 	var inTable bool
 	var columnSeq uint
+	var lastIndex *models.Index // most recent index in the current Indexes block
+	lineNo := 0
 
 	tableRegex := regexp.MustCompile(`^Table\s+(.+?)\s*{`)
 	refRegex := regexp.MustCompile(`^Ref:\s+(.+)`)
 
 	for scanner.Scan() {
+		lineNo++
 		line := strings.TrimSpace(scanner.Text())
 
 		// Skip empty lines and comments
@@ -447,6 +450,20 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 			continue
 		}
 
+		// Parse a dialect directive (@postgres:, @sqlite:, …). Handled before
+		// table/column/index parsing so directive lines are never mistaken for
+		// columns.
+		if strings.HasPrefix(line, "@") {
+			pd, err := parseDirectiveLine(line, lineNo)
+			if err != nil {
+				return nil, err
+			}
+			if err := r.attachDirective(pd, db, currentTable, inTable, inIndexes, lastIndex); err != nil {
+				return nil, err
+			}
+			continue
+		}
+
 		// Parse Table definition
 		if matches := tableRegex.FindStringSubmatch(line); matches != nil {
 			tableName := matches[1]
@@ -474,8 +491,10 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 			continue
 		}
 
-		// End of table definition
+		// End of table definition. Guarded by !inIndexes so the closing brace
-		if inTable && line == "}" {
+		// of an `indexes { }` block is not mistaken for the end of the table
+		// (which would drop any table-level content that follows it).
+		if inTable && !inIndexes && line == "}" {
 			if currentTable != nil && currentSchema != "" {
 				schemaMap[currentSchema].Tables = append(schemaMap[currentSchema].Tables, currentTable)
 				currentTable = nil
@@ -488,12 +507,14 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 		// Parse indexes section
 		if inTable && (strings.HasPrefix(line, "Indexes {") || strings.HasPrefix(line, "indexes {")) {
 			inIndexes = true
+			lastIndex = nil
 			continue
 		}
 
 		// End of indexes section
 		if inIndexes && line == "}" {
 			inIndexes = false
+			lastIndex = nil
 			continue
 		}
 
@@ -513,6 +534,7 @@ func (r *Reader) parseDBML(content string) (*models.Database, error) {
 			index := r.parseIndex(line, currentTable.Name, currentSchema)
 			if index != nil {
 				currentTable.Indexes[index.Name] = index
+				lastIndex = index
 			}
 			continue
 		}

pkg/readers/reader.go

@@ -28,6 +28,10 @@ type ReaderOptions struct {
 	// Prisma7 enables Prisma 7-specific handling for Prisma schemas.
 	Prisma7 bool
 
+	// StrictDirectives makes DBML dialect directives (@postgres:, @sqlite:, …)
+	// fail on an unknown namespace or key instead of preserving them silently.
+	StrictDirectives bool
+
 	// Additional options can be added here as needed
 	Metadata map[string]interface{}
 }

pkg/writers/dbml/README.md

@@ -137,6 +137,41 @@ indexes {
 }
 ```
 
+### Dialect directives
+
+Dialect directives stored on a model object's `Metadata` (namespace `postgres`,
+`sqlite`, …) are re-emitted verbatim, one line per directive, at the location
+they belong to:
+
+```dbml
+@postgres: search_path myapp
+
+Table myapp.events {
+  id bigint [pk]
+  created_at timestamp [not null]
+  @postgres(id): identity always
+  @postgres: partition by RANGE (created_at)
+  @sqlite: without rowid
+
+  indexes {
+    (created_at) [name: 'idx_events_created']
+    @postgres: with (fillfactor=90)
+  }
+}
+```
+
+| Emitted at | From |
+|------------|------|
+| Before the first table | `Database.Metadata` |
+| After a column line, as `@ns(col): …` | `Column.Metadata` |
+| After an index line, inside `indexes { }` | `Index.Metadata` |
+| After the `indexes` block, before `Note:` | `Table.Metadata` |
+
+Output is deterministic (ordered by namespace, then source line, then args), so a
+`DBML → model → DBML` round-trip is idempotent. See
+[`docs/DBML_DIRECTIVES.md`](../../../docs/DBML_DIRECTIVES.md) for the grammar and
+the list of directives the PostgreSQL and SQLite writers translate to SQL.
+
 ## Type Mapping
 
 | SQL Type | DBML Type |

pkg/writers/dbml/directives.go

@@ -0,0 +1,23 @@
+package dbml
+
+import (
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// directiveLines renders every dialect directive stored in meta back to its DBML
+// source form, one line per directive, each prefixed with indent. When target is
+// non-empty it is emitted as the "(column)" target, e.g.
+// "  @postgres(id): identity always". Order is deterministic (see
+// models.GetDirectives).
+func directiveLines(meta map[string]any, indent, target string) []string {
+	directives := models.GetDirectives(meta)
+	if len(directives) == 0 {
+		return nil
+	}
+
+	lines := make([]string, 0, len(directives))
+	for _, d := range directives {
+		lines = append(lines, indent+models.FormatDirectiveLine(d, target))
+	}
+	return lines
+}

pkg/writers/dbml/directives_test.go

@@ -0,0 +1,97 @@
+package dbml
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	dbmlreader "git.warky.dev/wdevs/relspecgo/pkg/readers/dbml"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+const directiveSrc = `@postgres: search_path myapp
+
+Table myapp.events {
+  id bigint [pk]
+  created_at timestamp [not null]
+  @postgres(id): identity always
+  @postgres: partition by RANGE (created_at)
+  @postgres: tablespace fast_data
+  @sqlite: without rowid
+
+  indexes {
+    (created_at) [name: 'idx_events_created']
+    @postgres: with (fillfactor=90)
+  }
+}
+`
+
+func writeDBML(t *testing.T, db *models.Database) string {
+	t.Helper()
+	out := filepath.Join(t.TempDir(), "out.dbml")
+	require.NoError(t, NewWriter(&writers.WriterOptions{OutputPath: out}).WriteDatabase(db))
+	b, err := os.ReadFile(out)
+	require.NoError(t, err)
+	return string(b)
+}
+
+func readDBML(t *testing.T, src string) *models.Database {
+	t.Helper()
+	f := filepath.Join(t.TempDir(), "in.dbml")
+	require.NoError(t, os.WriteFile(f, []byte(src), 0o644))
+	db, err := dbmlreader.NewReader(&readers.ReaderOptions{FilePath: f}).ReadDatabase()
+	require.NoError(t, err)
+	return db
+}
+
+func collectDirectives(db *models.Database) map[string][]string {
+	got := map[string][]string{}
+	add := func(loc string, meta map[string]any) {
+		for _, d := range models.GetDirectives(meta) {
+			got[loc] = append(got[loc], models.FormatDirectiveLine(d, ""))
+		}
+	}
+	add("database", db.Metadata)
+	for _, s := range db.Schemas {
+		for _, tbl := range s.Tables {
+			add("table:"+tbl.Name, tbl.Metadata)
+			for _, c := range tbl.Columns {
+				add("column:"+c.Name, c.Metadata)
+			}
+			for _, i := range tbl.Indexes {
+				add("index:"+i.Name, i.Metadata)
+			}
+		}
+	}
+	return got
+}
+
+func TestDirectives_RoundTrip(t *testing.T) {
+	db1 := readDBML(t, directiveSrc)
+	out1 := writeDBML(t, db1)
+	db2 := readDBML(t, out1)
+	out2 := writeDBML(t, db2)
+
+	assert.Equal(t, out1, out2, "DBML directive output should be idempotent")
+	assert.Equal(t, collectDirectives(db1), collectDirectives(db2), "directives preserved through round-trip")
+
+	// Spot-check each location survived.
+	d := collectDirectives(db2)
+	assert.Contains(t, d["database"], "@postgres: search_path myapp")
+	assert.Contains(t, d["table:events"], "@postgres: partition by RANGE (created_at)")
+	assert.Contains(t, d["table:events"], "@sqlite: without rowid")
+	assert.Contains(t, d["column:id"], "@postgres: identity always")
+	assert.Contains(t, d["index:idx_events_created"], "@postgres: with (fillfactor=90)")
+}
+
+func TestDirectives_WriterEmitsColumnTarget(t *testing.T) {
+	db := readDBML(t, directiveSrc)
+	out := writeDBML(t, db)
+	assert.Contains(t, out, "@postgres(id): identity always")
+}

pkg/writers/dbml/writer.go

@@ -72,6 +72,14 @@ func (w *Writer) databaseToDBML(d *models.Database) string {
 		sb.WriteString("\n")
 	}
 
+	if dirLines := directiveLines(d.Metadata, "", ""); len(dirLines) > 0 {
+		for _, line := range dirLines {
+			sb.WriteString(line)
+			sb.WriteString("\n")
+		}
+		sb.WriteString("\n")
+	}
+
 	for _, schema := range d.Schemas {
 		sb.WriteString(w.schemaToDBML(schema))
 	}
@@ -146,6 +154,11 @@ func (w *Writer) tableToDBML(t *models.Table) string {
 			fmt.Fprintf(&sb, " // %s", column.Comment)
 		}
 		sb.WriteString("\n")
+
+		for _, line := range directiveLines(column.Metadata, "  ", column.Name) {
+			sb.WriteString(line)
+			sb.WriteString("\n")
+		}
 	}
 
 	if len(t.Indexes) > 0 {
@@ -167,10 +180,20 @@ func (w *Writer) tableToDBML(t *models.Table) string {
 				fmt.Fprintf(&sb, " [%s]", strings.Join(indexAttrs, ", "))
 			}
 			sb.WriteString("\n")
+
+			for _, line := range directiveLines(index.Metadata, "    ", "") {
+				sb.WriteString(line)
+				sb.WriteString("\n")
+			}
 		}
 		sb.WriteString("  }\n")
 	}
 
+	for _, line := range directiveLines(t.Metadata, "  ", "") {
+		sb.WriteString(line)
+		sb.WriteString("\n")
+	}
+
 	note := strings.TrimSpace(t.Description + " " + t.Comment)
 	if note != "" {
 		fmt.Fprintf(&sb, "\n  Note: '%s'\n", note)

pkg/writers/pgsql/README.md

@@ -172,6 +172,26 @@ When `include_audit` is enabled, adds:
 - Concurrent index creation (`CREATE INDEX CONCURRENTLY`) via `Index.Concurrent`
 - Check constraints with expressions
 - Extension types and indexes: PostGIS, pgvector, citext, hstore, ltree (see below)
+- DBML dialect directives (`@postgres:` — see below)
+
+### DBML dialect directives
+
+`@postgres:` directives carried on a model object's `Metadata` (typically from a
+DBML source file) are translated to SQL:
+
+| Directive | Location | Emitted |
+|-----------|----------|---------|
+| `@postgres: partition by …` | table | `PARTITION BY …` on `CREATE TABLE` |
+| `@postgres: inherits …` | table | `INHERITS (…)` |
+| `@postgres: with (…)` | table, index | `WITH (…)` (on an index, overrides the comment-derived `WITH`) |
+| `@postgres: tablespace …` | table, index | `TABLESPACE …` |
+| `@postgres(col): storage …` | column | `STORAGE …` |
+| `@postgres(col): compression …` | column | `COMPRESSION …` |
+| `@postgres(col): identity always` / `identity by default` | column | `GENERATED ALWAYS/BY DEFAULT AS IDENTITY` |
+
+Directives for other dialects (`@sqlite:` …) are ignored. With
+`WriterOptions.StrictDirectives` (CLI `--strict-directives`) an untranslatable
+`@postgres:` key is an error. Full reference: [`docs/DBML_DIRECTIVES.md`](../../../docs/DBML_DIRECTIVES.md).
 
 ## Data Types
 

pkg/writers/pgsql/directives.go

@@ -0,0 +1,184 @@
+package pgsql
+
+import (
+	"fmt"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// directiveNamespace is the dialect namespace this writer consumes. Directives
+// for other namespaces (e.g. "sqlite") are ignored and never emitted as SQL.
+const directiveNamespace = "postgres"
+
+// pgHandledDirectives maps a directive location to the set of postgres keys this
+// writer knows how to translate. In strict mode an unknown key for this
+// namespace at a supported location is a hard error.
+var pgHandledDirectives = map[string]map[string]bool{
+	models.DirectiveLocationTable:  {"partition": true, "inherits": true, "with": true, "tablespace": true},
+	models.DirectiveLocationColumn: {"storage": true, "compression": true, "identity": true},
+	models.DirectiveLocationIndex:  {"with": true, "tablespace": true},
+}
+
+// checkDirectives validates postgres directives across a schema when strict mode
+// is enabled. It returns an error for any postgres directive whose key this
+// writer cannot translate. With strict mode off it is a no-op.
+func (w *Writer) checkDirectives(schema *models.Schema) error {
+	if w.options == nil || !w.options.StrictDirectives {
+		return nil
+	}
+	for _, table := range schema.Tables {
+		if err := checkObjectDirectives(table.Metadata, models.DirectiveLocationTable, table.Name); err != nil {
+			return err
+		}
+		for _, col := range table.Columns {
+			if err := checkObjectDirectives(col.Metadata, models.DirectiveLocationColumn, table.Name+"."+col.Name); err != nil {
+				return err
+			}
+		}
+		for _, idx := range table.Indexes {
+			if err := checkObjectDirectives(idx.Metadata, models.DirectiveLocationIndex, idx.Name); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func checkObjectDirectives(meta map[string]any, location, owner string) error {
+	for _, d := range models.DirectivesForNamespace(meta, directiveNamespace) {
+		if !pgHandledDirectives[location][d.Key] {
+			return fmt.Errorf("pgsql: %s: unsupported @postgres directive %q at %s level (strict mode)", owner, d.Key, location)
+		}
+	}
+	return nil
+}
+
+// upperLeadingClause upcases a known leading keyword phrase in a directive
+// argument so the emitted SQL reads conventionally. Identifiers that follow are
+// left untouched.
+func upperLeadingClause(args, lowerPrefix, upperPrefix string) string {
+	args = strings.TrimSpace(args)
+	if strings.HasPrefix(strings.ToLower(args), lowerPrefix) {
+		return upperPrefix + args[len(lowerPrefix):]
+	}
+	return args
+}
+
+// pgTableDirectiveSuffix returns the clause appended after the closing ")" of a
+// CREATE TABLE statement, e.g. " PARTITION BY RANGE (created_at) TABLESPACE fast".
+func pgTableDirectiveSuffix(table *models.Table) string {
+	directives := models.DirectivesForNamespace(table.Metadata, directiveNamespace)
+	if len(directives) == 0 {
+		return ""
+	}
+
+	byKey := firstByKey(directives)
+
+	var parts []string
+	if d, ok := byKey["partition"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "partition by", "PARTITION BY"))
+	}
+	if d, ok := byKey["inherits"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "inherits", "INHERITS"))
+	}
+	if d, ok := byKey["with"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "with", "WITH"))
+	}
+	if d, ok := byKey["tablespace"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "tablespace", "TABLESPACE"))
+	}
+	if len(parts) == 0 {
+		return ""
+	}
+	return " " + strings.Join(parts, " ")
+}
+
+// pgColumnDirectiveSuffix returns the clause appended to a column definition,
+// e.g. " STORAGE PLAIN" or " GENERATED ALWAYS AS IDENTITY".
+func pgColumnDirectiveSuffix(col *models.Column) string {
+	directives := models.DirectivesForNamespace(col.Metadata, directiveNamespace)
+	if len(directives) == 0 {
+		return ""
+	}
+	byKey := firstByKey(directives)
+
+	var parts []string
+	if d, ok := byKey["storage"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "storage", "STORAGE"))
+	}
+	if d, ok := byKey["compression"]; ok {
+		parts = append(parts, upperLeadingClause(d.Args, "compression", "COMPRESSION"))
+	}
+	if d, ok := byKey["identity"]; ok {
+		parts = append(parts, identityClause(d.Args))
+	}
+	if len(parts) == 0 {
+		return ""
+	}
+	return " " + strings.Join(parts, " ")
+}
+
+// identityClause maps the two documented identity forms to standard SQL,
+// falling back to a verbatim (upcased-keyword) rendering.
+func identityClause(args string) string {
+	switch strings.ToLower(strings.Join(strings.Fields(args), " ")) {
+	case "identity always":
+		return "GENERATED ALWAYS AS IDENTITY"
+	case "identity default", "identity by default":
+		return "GENERATED BY DEFAULT AS IDENTITY"
+	default:
+		return upperLeadingClause(args, "identity", "IDENTITY")
+	}
+}
+
+// pgIndexDirectiveWith returns the parenthesised storage-parameter list from an
+// @postgres: with (...) index directive, e.g. "fillfactor=90", or "".
+func pgIndexDirectiveWith(index *models.Index) string {
+	for _, d := range models.DirectivesForNamespace(index.Metadata, directiveNamespace) {
+		if d.Key != "with" {
+			continue
+		}
+		inner := d.Args
+		if i := strings.Index(inner, "("); i >= 0 {
+			if j := strings.LastIndex(inner, ")"); j > i {
+				return strings.TrimSpace(inner[i+1 : j])
+			}
+		}
+		return strings.TrimSpace(strings.TrimPrefix(strings.ToLower(inner), "with"))
+	}
+	return ""
+}
+
+// pgIndexWithParams returns the storage-parameter list to use for an index,
+// preferring an @postgres: with (...) directive over the given fallback (e.g.
+// one derived from the index comment).
+func pgIndexWithParams(index *models.Index, fallback string) string {
+	if p := pgIndexDirectiveWith(index); p != "" {
+		return p
+	}
+	return fallback
+}
+
+// pgIndexDirectiveTablespace returns the tablespace name from an
+// @postgres: tablespace <name> index directive, or "".
+func pgIndexDirectiveTablespace(index *models.Index) string {
+	for _, d := range models.DirectivesForNamespace(index.Metadata, directiveNamespace) {
+		if d.Key == "tablespace" {
+			return strings.TrimSpace(strings.TrimPrefix(strings.ToLower(d.Args), "tablespace"))
+		}
+	}
+	return ""
+}
+
+// firstByKey indexes directives by key, keeping the first occurrence (the
+// documented postgres keys used here are all singletons).
+func firstByKey(directives []models.Directive) map[string]models.Directive {
+	byKey := make(map[string]models.Directive, len(directives))
+	for _, d := range directives {
+		if _, exists := byKey[d.Key]; !exists {
+			byKey[d.Key] = d
+		}
+	}
+	return byKey
+}

pkg/writers/pgsql/directives_test.go

@@ -0,0 +1,107 @@
+package pgsql
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+func directiveTestDB(t *testing.T) *models.Database {
+	t.Helper()
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+	table := models.InitTable("events", "public")
+
+	id := models.InitColumn("id", "events", "public")
+	id.Type = "bigint"
+	id.IsPrimaryKey = true
+	id.NotNull = true
+	models.AddDirective(id.Metadata, models.Directive{Namespace: "postgres", Args: "identity always"})
+	models.AddDirective(id.Metadata, models.Directive{Namespace: "sqlite", Args: "collate NOCASE"})
+	table.Columns["id"] = id
+
+	created := models.InitColumn("created_at", "events", "public")
+	created.Type = "timestamp"
+	created.NotNull = true
+	table.Columns["created_at"] = created
+
+	models.AddDirective(table.Metadata, models.Directive{Namespace: "postgres", Args: "partition by RANGE (created_at)"})
+	models.AddDirective(table.Metadata, models.Directive{Namespace: "postgres", Args: "tablespace fast_data"})
+	models.AddDirective(table.Metadata, models.Directive{Namespace: "sqlite", Args: "without rowid"})
+
+	idx := models.InitIndex("idx_events_created", "events", "public")
+	idx.Columns = []string{"created_at"}
+	models.AddDirective(idx.Metadata, models.Directive{Namespace: "postgres", Args: "with (fillfactor=90)"})
+	models.AddDirective(idx.Metadata, models.Directive{Namespace: "postgres", Args: "tablespace idx_space"})
+	table.Indexes["idx_events_created"] = idx
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+	return db
+}
+
+func TestPgDirectives_WriteDatabasePath(t *testing.T) {
+	var buf bytes.Buffer
+	w := NewWriter(&writers.WriterOptions{})
+	w.writer = &buf
+	if err := w.WriteDatabase(directiveTestDB(t)); err != nil {
+		t.Fatalf("WriteDatabase: %v", err)
+	}
+	out := buf.String()
+
+	for _, want := range []string{
+		") PARTITION BY RANGE (created_at) TABLESPACE fast_data",
+		"GENERATED ALWAYS AS IDENTITY",
+		"WITH (fillfactor=90) TABLESPACE idx_space",
+	} {
+		if !strings.Contains(out, want) {
+			t.Errorf("missing %q in:\n%s", want, out)
+		}
+	}
+	// sqlite directives must never reach PG output.
+	if strings.Contains(out, "WITHOUT ROWID") || strings.Contains(strings.ToUpper(out), "COLLATE NOCASE") {
+		t.Errorf("sqlite directive leaked into PG output:\n%s", out)
+	}
+}
+
+func TestPgDirectives_WriteSchemaPath(t *testing.T) {
+	var buf bytes.Buffer
+	w := NewWriter(&writers.WriterOptions{})
+	w.writer = &buf
+	if err := w.WriteSchema(directiveTestDB(t).Schemas[0]); err != nil {
+		t.Fatalf("WriteSchema: %v", err)
+	}
+	out := buf.String()
+	if !strings.Contains(out, ") PARTITION BY RANGE (created_at) TABLESPACE fast_data;") {
+		t.Errorf("table suffix missing from WriteSchema path:\n%s", out)
+	}
+	if !strings.Contains(out, "WITH (fillfactor=90) TABLESPACE idx_space") {
+		t.Errorf("index clauses missing from WriteSchema path:\n%s", out)
+	}
+}
+
+func TestPgDirectives_StrictUnknownKeyErrors(t *testing.T) {
+	db := directiveTestDB(t)
+	models.AddDirective(db.Schemas[0].Tables[0].Metadata, models.Directive{Namespace: "postgres", Args: "frobnicate x"})
+
+	var buf bytes.Buffer
+	w := NewWriter(&writers.WriterOptions{StrictDirectives: true})
+	w.writer = &buf
+	err := w.WriteSchema(db.Schemas[0])
+	if err == nil || !strings.Contains(err.Error(), "frobnicate") {
+		t.Fatalf("want strict error for unknown postgres key, got %v", err)
+	}
+}
+
+func TestPgDirectives_StrictIgnoresOtherNamespaces(t *testing.T) {
+	// sqlite directives are present but must not trip PG strict mode.
+	var buf bytes.Buffer
+	w := NewWriter(&writers.WriterOptions{StrictDirectives: true})
+	w.writer = &buf
+	if err := w.WriteSchema(directiveTestDB(t).Schemas[0]); err != nil {
+		t.Fatalf("strict mode should ignore non-postgres directives, got %v", err)
+	}
+}

pkg/writers/pgsql/writer.go

@@ -143,6 +143,10 @@ func (w *Writer) GenerateDatabaseStatements(db *models.Database) ([]string, erro
 func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, error) {
 	statements := []string{}
 
+	if err := w.checkDirectives(schema); err != nil {
+		return nil, err
+	}
+
 	// Phase 1: Create schema (skip entirely when flattening)
 	if schema.Name != "public" && !w.options.FlattenSchema {
 		statements = append(statements, fmt.Sprintf("-- Schema: %s", schema.Name))
@@ -277,17 +281,22 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 			columnExprs := buildIndexColumnExpressions(table, index, indexType)
 
 			withClause := ""
-			if params := indexStorageParameters(index.Comment); params != "" {
+			if params := pgIndexWithParams(index, indexStorageParameters(index.Comment)); params != "" {
 				withClause = fmt.Sprintf(" WITH (%s)", params)
 			}
 
+			tablespaceClause := ""
+			if ts := pgIndexDirectiveTablespace(index); ts != "" {
+				tablespaceClause = fmt.Sprintf(" TABLESPACE %s", ts)
+			}
+
 			whereClause := ""
 			if index.Where != "" {
 				whereClause = fmt.Sprintf(" WHERE %s", index.Where)
 			}
 
-			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s USING %s (%s)%s%s",
+			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s USING %s (%s)%s%s%s",
-				uniqueStr, quoteIdentifier(index.Name), w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), withClause, whereClause)
+				uniqueStr, quoteIdentifier(index.Name), w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), withClause, tablespaceClause, whereClause)
 			statements = append(statements, stmt)
 		}
 	}
@@ -581,8 +590,9 @@ func (w *Writer) generateCreateTableStatement(schema *models.Schema, table *mode
 		columnDefs = append(columnDefs, "  "+def)
 	}
 
-	stmt := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s (\n%s\n)",
+	stmt := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s (\n%s\n)%s",
-		w.qualTable(schema.SQLName(), table.SQLName()), strings.Join(columnDefs, ",\n"))
+		w.qualTable(schema.SQLName(), table.SQLName()), strings.Join(columnDefs, ",\n"),
+		pgTableDirectiveSuffix(table))
 	statements = append(statements, stmt)
 
 	return statements, nil
@@ -611,7 +621,7 @@ func (w *Writer) generateColumnDefinition(col *models.Column) string {
 		}
 	}
 
-	return strings.Join(parts, " ")
+	return strings.Join(parts, " ") + pgColumnDirectiveSuffix(col)
 }
 
 func effectiveColumnSQLType(col *models.Column) string {
@@ -678,6 +688,10 @@ func (w *Writer) WriteSchema(schema *models.Schema) error {
 		w.writer = os.Stdout
 	}
 
+	if err := w.checkDirectives(schema); err != nil {
+		return err
+	}
+
 	// Phase 1: Create schema (priority 1)
 	if err := w.writeCreateSchema(schema); err != nil {
 		return err
@@ -884,7 +898,7 @@ func (w *Writer) writeCreateTables(schema *models.Schema) error {
 		}
 
 		fmt.Fprintf(w.writer, "%s\n", strings.Join(columnDefs, ",\n"))
-		fmt.Fprintf(w.writer, ");\n\n")
+		fmt.Fprintf(w.writer, ")%s;\n\n", pgTableDirectiveSuffix(table))
 	}
 
 	return nil
@@ -1079,10 +1093,15 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 			}
 
 			withClause := ""
-			if params := indexStorageParameters(index.Comment); params != "" {
+			if params := pgIndexWithParams(index, indexStorageParameters(index.Comment)); params != "" {
 				withClause = fmt.Sprintf(" WITH (%s)", params)
 			}
 
+			tablespaceClause := ""
+			if ts := pgIndexDirectiveTablespace(index); ts != "" {
+				tablespaceClause = fmt.Sprintf(" TABLESPACE %s", ts)
+			}
+
 			whereClause := ""
 			if index.Where != "" {
 				whereClause = fmt.Sprintf(" WHERE %s", index.Where)
@@ -1095,8 +1114,8 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 
 			fmt.Fprintf(w.writer, "CREATE %sINDEX %sIF NOT EXISTS %s\n",
 				unique, concurrently, indexName)
-			fmt.Fprintf(w.writer, "  ON %s USING %s (%s)%s%s;\n\n",
+			fmt.Fprintf(w.writer, "  ON %s USING %s (%s)%s%s%s;\n\n",
-				w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), withClause, whereClause)
+				w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), withClause, tablespaceClause, whereClause)
 		}
 	}
 

pkg/writers/sqlite/README.md

@@ -118,6 +118,21 @@ CREATE TABLE "posts" (
 - **Check Constraints**: Generated as comments (should be added to CREATE TABLE manually)
 - **Indexes**: Generated without PostgreSQL-specific features (no GIN, GiST, operator classes)
 
+## DBML dialect directives
+
+`@sqlite:` directives carried on a model object's `Metadata` (typically from a
+DBML source file) are translated to SQL:
+
+| Directive | Location | Emitted |
+|-----------|----------|---------|
+| `@sqlite: without rowid` | table | `WITHOUT ROWID` table option |
+| `@sqlite: strict` | table | `STRICT` table option (after `WITHOUT ROWID`) |
+| `@sqlite(col): collate …` | column | ` COLLATE …` in the column definition |
+
+Directives for other dialects (`@postgres:` …) are ignored. With
+`WriterOptions.StrictDirectives` (CLI `--strict-directives`) an untranslatable
+`@sqlite:` key is an error. Full reference: [`docs/DBML_DIRECTIVES.md`](../../../docs/DBML_DIRECTIVES.md).
+
 ## Output Structure
 
 Generated SQL follows this order:

pkg/writers/sqlite/directives.go

@@ -0,0 +1,84 @@
+package sqlite
+
+import (
+	"fmt"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// directiveNamespace is the dialect namespace this writer consumes. Directives
+// for other namespaces (e.g. "postgres") are ignored and never emitted as SQL.
+const directiveNamespace = "sqlite"
+
+// sqliteHandledDirectives maps a directive location to the set of sqlite keys
+// this writer knows how to translate. In strict mode an unknown key for this
+// namespace at a supported location is a hard error.
+var sqliteHandledDirectives = map[string]map[string]bool{
+	models.DirectiveLocationTable:  {"without": true, "strict": true},
+	models.DirectiveLocationColumn: {"collate": true},
+}
+
+// checkDirectives validates sqlite directives across a schema when strict mode
+// is enabled. With strict mode off it is a no-op.
+func (w *Writer) checkDirectives(schema *models.Schema) error {
+	if w.options == nil || !w.options.StrictDirectives {
+		return nil
+	}
+	for _, table := range schema.Tables {
+		if err := checkObjectDirectives(table.Metadata, models.DirectiveLocationTable, table.Name); err != nil {
+			return err
+		}
+		for _, col := range table.Columns {
+			if err := checkObjectDirectives(col.Metadata, models.DirectiveLocationColumn, table.Name+"."+col.Name); err != nil {
+				return err
+			}
+		}
+		for _, idx := range table.Indexes {
+			if err := checkObjectDirectives(idx.Metadata, models.DirectiveLocationIndex, idx.Name); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func checkObjectDirectives(meta map[string]any, location, owner string) error {
+	for _, d := range models.DirectivesForNamespace(meta, directiveNamespace) {
+		if !sqliteHandledDirectives[location][d.Key] {
+			return fmt.Errorf("sqlite: %s: unsupported @sqlite directive %q at %s level (strict mode)", owner, d.Key, location)
+		}
+	}
+	return nil
+}
+
+// sqliteTableOptions returns the trailing table-option clause for a CREATE TABLE
+// statement, e.g. "WITHOUT ROWID, STRICT". WITHOUT ROWID is emitted before
+// STRICT, matching SQLite's own grammar ordering.
+func sqliteTableOptions(table *models.Table) string {
+	var opts []string
+	if models.HasDirective(table.Metadata, directiveNamespace, "without") {
+		opts = append(opts, "WITHOUT ROWID")
+	}
+	if models.HasDirective(table.Metadata, directiveNamespace, "strict") {
+		opts = append(opts, "STRICT")
+	}
+	return strings.Join(opts, ", ")
+}
+
+// sqliteColumnCollate returns a " COLLATE <name>" clause for a column carrying an
+// @sqlite(col): collate <name> directive, or "".
+func sqliteColumnCollate(col *models.Column) string {
+	for _, d := range models.DirectivesForNamespace(col.Metadata, directiveNamespace) {
+		if d.Key != "collate" {
+			continue
+		}
+		name := strings.TrimSpace(strings.TrimPrefix(strings.TrimSpace(d.Args), "collate"))
+		name = strings.TrimSpace(name)
+		if name == "" {
+			return ""
+		}
+		return " COLLATE " + name
+	}
+	return ""
+}

pkg/writers/sqlite/directives_test.go

@@ -0,0 +1,82 @@
+package sqlite
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+func sqliteDirectiveDB(t *testing.T) *models.Database {
+	t.Helper()
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+	table := models.InitTable("events", "public")
+
+	id := models.InitColumn("id", "events", "public")
+	id.Type = "bigint"
+	id.IsPrimaryKey = true
+	id.NotNull = true
+	table.Columns["id"] = id
+
+	name := models.InitColumn("name", "events", "public")
+	name.Type = "varchar(200)"
+	name.NotNull = true
+	models.AddDirective(name.Metadata, models.Directive{Namespace: "sqlite", Args: "collate NOCASE"})
+	// A postgres directive on the same column must be ignored by the sqlite writer.
+	models.AddDirective(name.Metadata, models.Directive{Namespace: "postgres", Args: "storage plain"})
+	table.Columns["name"] = name
+
+	models.AddDirective(table.Metadata, models.Directive{Namespace: "sqlite", Args: "without rowid"})
+	models.AddDirective(table.Metadata, models.Directive{Namespace: "sqlite", Args: "strict"})
+	models.AddDirective(table.Metadata, models.Directive{Namespace: "postgres", Args: "partition by RANGE (id)"})
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+	return db
+}
+
+func TestSqliteDirectives_TableOptionsAndCollate(t *testing.T) {
+	var buf bytes.Buffer
+	w := NewWriter(&writers.WriterOptions{})
+	w.writer = &buf
+	if err := w.WriteDatabase(sqliteDirectiveDB(t)); err != nil {
+		t.Fatalf("WriteDatabase: %v", err)
+	}
+	out := buf.String()
+
+	if !strings.Contains(out, ") WITHOUT ROWID, STRICT;") {
+		t.Errorf("missing table options clause:\n%s", out)
+	}
+	if !strings.Contains(out, `"name" TEXT COLLATE NOCASE NOT NULL`) {
+		t.Errorf("missing column COLLATE clause:\n%s", out)
+	}
+	// postgres directives must never reach sqlite output.
+	if strings.Contains(strings.ToUpper(out), "PARTITION BY") || strings.Contains(strings.ToUpper(out), "STORAGE PLAIN") {
+		t.Errorf("postgres directive leaked into sqlite output:\n%s", out)
+	}
+}
+
+func TestSqliteDirectives_StrictUnknownKeyErrors(t *testing.T) {
+	db := sqliteDirectiveDB(t)
+	models.AddDirective(db.Schemas[0].Tables[0].Metadata, models.Directive{Namespace: "sqlite", Args: "frobnicate x"})
+
+	var buf bytes.Buffer
+	w := NewWriter(&writers.WriterOptions{StrictDirectives: true})
+	w.writer = &buf
+	err := w.WriteDatabase(db)
+	if err == nil || !strings.Contains(err.Error(), "frobnicate") {
+		t.Fatalf("want strict error for unknown sqlite key, got %v", err)
+	}
+}
+
+func TestSqliteDirectives_StrictIgnoresPostgres(t *testing.T) {
+	var buf bytes.Buffer
+	w := NewWriter(&writers.WriterOptions{StrictDirectives: true})
+	w.writer = &buf
+	if err := w.WriteDatabase(sqliteDirectiveDB(t)); err != nil {
+		t.Fatalf("strict mode should ignore postgres directives, got %v", err)
+	}
+}

pkg/writers/sqlite/template_functions.go

@@ -22,9 +22,10 @@ func GetTemplateFuncs(opts *writers.WriterOptions) template.FuncMap {
 		"format_constraint_name": func(schema, table, constraint string) string {
 			return FormatConstraintName(schema, table, constraint, opts)
 		},
-		"join":  strings.Join,
+		"join":           strings.Join,
-		"lower": strings.ToLower,
+		"lower":          strings.ToLower,
-		"upper": strings.ToUpper,
+		"upper":          strings.ToUpper,
+		"column_collate": sqliteColumnCollate,
 	}
 }
 

pkg/writers/sqlite/templates.go

@@ -40,11 +40,12 @@ func NewTemplateExecutor(opts *writers.WriterOptions) (*TemplateExecutor, error)
 
 // TableTemplateData contains data for table template
 type TableTemplateData struct {
-	Schema      string
+	Schema       string
-	Name        string
+	Name         string
-	Columns     []*models.Column
+	Columns      []*models.Column
-	PrimaryKey  *models.Constraint
+	PrimaryKey   *models.Constraint
-	ForeignKeys []ForeignKeyTemplateData
+	ForeignKeys  []ForeignKeyTemplateData
+	TableOptions string
 }
 
 // ForeignKeyTemplateData contains data for an inline FOREIGN KEY clause
@@ -188,11 +189,12 @@ func BuildTableTemplateData(schema string, table *models.Table) TableTemplateDat
 	}
 
 	return TableTemplateData{
-		Schema:      schema,
+		Schema:       schema,
-		Name:        table.Name,
+		Name:         table.Name,
-		Columns:     columns,
+		Columns:      columns,
-		PrimaryKey:  pk,
+		PrimaryKey:   pk,
-		ForeignKeys: fks,
+		ForeignKeys:  fks,
+		TableOptions: sqliteTableOptions(table),
 	}
 }
 

pkg/writers/sqlite/templates/create_table.tmpl

@@ -1,7 +1,7 @@
 CREATE TABLE {{quote_ident (qualified_table_name .Schema .Name)}} (
 {{- $hasAutoIncrement := false}}
 {{- range $i, $col := .Columns}}{{if $i}},{{end}}
-    {{quote_ident $col.Name}} {{map_type $col.Type}}{{if is_autoincrement $col}}{{$hasAutoIncrement = true}} PRIMARY KEY AUTOINCREMENT{{else}}{{if $col.NotNull}} NOT NULL{{end}}{{if ne (format_default $col) ""}} DEFAULT {{format_default $col}}{{end}}{{end}}
+    {{quote_ident $col.Name}} {{map_type $col.Type}}{{column_collate $col}}{{if is_autoincrement $col}}{{$hasAutoIncrement = true}} PRIMARY KEY AUTOINCREMENT{{else}}{{if $col.NotNull}} NOT NULL{{end}}{{if ne (format_default $col) ""}} DEFAULT {{format_default $col}}{{end}}{{end}}
 {{- end}}
 {{- if and .PrimaryKey (not $hasAutoIncrement)}}{{if gt (len .Columns) 0}},{{end}}
     PRIMARY KEY ({{range $i, $colName := .PrimaryKey.Columns}}{{if $i}}, {{end}}{{quote_ident $colName}}{{end}})
@@ -9,4 +9,4 @@ CREATE TABLE {{quote_ident (qualified_table_name .Schema .Name)}} (
 {{- range .ForeignKeys}},
     FOREIGN KEY ({{range $i, $col := .Columns}}{{if $i}}, {{end}}{{quote_ident $col}}{{end}}) REFERENCES {{quote_ident (qualified_table_name .ForeignSchema .ForeignTable)}} ({{range $i, $col := .ForeignColumns}}{{if $i}}, {{end}}{{quote_ident $col}}{{end}}){{if .OnDelete}} ON DELETE {{.OnDelete}}{{end}}{{if .OnUpdate}} ON UPDATE {{.OnUpdate}}{{end}}
 {{- end}}
-);
+){{if .TableOptions}} {{.TableOptions}}{{end}};

pkg/writers/sqlite/writer.go

@@ -186,6 +186,10 @@ func tableSchemaName(schema string) string {
 func (w *Writer) WriteSchema(schema *models.Schema) error {
 	tableSchema := tableSchemaName(schema.Name)
 
+	if err := w.checkDirectives(schema); err != nil {
+		return err
+	}
+
 	// SQLite doesn't have schemas, so we just write a comment (skip for the
 	// default schema, since its tables aren't actually being prefixed)
 	if tableSchema != "" {

pkg/writers/writer.go

@@ -86,6 +86,10 @@ type WriterOptions struct {
 	// Prisma7 enables Prisma 7-specific output for Prisma writers.
 	Prisma7 bool
 
+	// StrictDirectives makes dialect directive translation fail on an
+	// unsupported key for the writer's own namespace instead of skipping it.
+	StrictDirectives bool
+
 	// ContinueOnError instructs SQL writers to prepend `\set ON_ERROR_STOP off`
 	// to their output so that psql continues past errors instead of stopping.
 	ContinueOnError bool