feat: mark generated and identity columns across writers and DBML

- bun: scanonly+generated for GENERATED columns; scanonly+identity for ALWAYS identity (PK gets identity only)
- gorm: <-:false+generated / identity, same primary key rule
- dbml: write GENERATED/IDENTITY column notes and read them back into the model
- pgsql: emit generation/identity clauses in migration create-table and add-column, no DEFAULT
- readmes updated

pkg/readers/dbml/README.md

@@ -157,6 +157,7 @@ grammar and the supported-directive matrix.
 
 ## Notes
 
+- Column notes `GENERATED ALWAYS AS (expr) STORED` and `GENERATED ALWAYS|BY DEFAULT AS IDENTITY` set `Generated`/`GenerationExpression` and `Identity`/`IdentityGeneration`; they are not kept as comments
 - DBML is designed for database documentation and diagramming
 - Schema name defaults to `public`
 - Relationship cardinality is preserved

pkg/readers/dbml/generated_columns.go

@@ -0,0 +1,38 @@
+package dbml
+
+import (
+	"regexp"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+var (
+	generatedNoteRegex = regexp.MustCompile(`(?is)^GENERATED\s+ALWAYS\s+AS\s*\((.*)\)\s*STORED$`)
+	identityNoteRegex  = regexp.MustCompile(`(?i)^GENERATED\s+(ALWAYS|BY\s+DEFAULT)\s+AS\s+IDENTITY$`)
+)
+
+// applyColumnMarkerNote interprets a column note written by the DBML writer for
+// GENERATED ... STORED and GENERATED ... AS IDENTITY columns, setting the matching
+// model fields. It returns true when the note was a marker, in which case it is not
+// a user comment.
+func applyColumnMarkerNote(column *models.Column, rawNote string) bool {
+	note := strings.TrimSpace(rawNote)
+	if len(note) >= 2 && (note[0] == '\'' || note[0] == '"') && note[len(note)-1] == note[0] {
+		note = note[1 : len(note)-1]
+	}
+	note = strings.ReplaceAll(strings.ReplaceAll(note, `\'`, `'`), `\\`, `\`)
+	note = strings.TrimSpace(note)
+
+	if m := generatedNoteRegex.FindStringSubmatch(note); m != nil {
+		column.Generated = true
+		column.GenerationExpression = strings.TrimSpace(m[1])
+		return true
+	}
+	if m := identityNoteRegex.FindStringSubmatch(note); m != nil {
+		column.Identity = true
+		column.IdentityGeneration = strings.Join(strings.Fields(strings.ToUpper(m[1])), " ")
+		return true
+	}
+	return false
+}

pkg/readers/dbml/reader.go

@@ -804,7 +804,9 @@ func (r *Reader) parseColumn(line, tableName, schemaName string) (*models.Column
 			} else if strings.HasPrefix(attr, "note:") {
 				// Parse column note/comment
 				note := strings.TrimSpace(strings.TrimPrefix(attr, "note:"))
-				column.Comment = strings.Trim(note, "'\"")
+				if !applyColumnMarkerNote(column, note) {
+					column.Comment = strings.Trim(note, "'\"")
+				}
 			} else if strings.HasPrefix(attr, "ref:") {
 				// Parse inline reference
 				// DBML semantics depend on context:

pkg/writers/bun/README.md

@@ -129,6 +129,9 @@ type User struct {
 - `default` - Default value
 - `rel` - Relationship definition
 - `type` - Explicit SQL type
+- `scanonly` - Excluded from INSERT/UPDATE: `GENERATED ... STORED` columns, and `GENERATED ALWAYS AS IDENTITY` columns that are not the primary key
+- `generated` - Marks a `GENERATED ... STORED` column
+- `identity` - Marks a `GENERATED ALWAYS AS IDENTITY` column (a primary key gets only this marker, since Bun drops `scanonly` fields from the PK list)
 
 ## Type Mapping
 

pkg/writers/bun/generated_column_test.go

@@ -0,0 +1,46 @@
+package bun
+
+import (
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestBuildBunTag_GeneratedColumn(t *testing.T) {
+	mapper := NewTypeMapper("", "")
+
+	generated := models.InitColumn("full_name", "users", "public")
+	generated.Type = "text"
+	generated.Generated = true
+	generated.GenerationExpression = "first || ' ' || last"
+
+	plain := models.InitColumn("first", "users", "public")
+	plain.Type = "text"
+
+	tests := []struct {
+		name   string
+		column *models.Column
+		want   bool
+	}{
+		{"generated column is scanonly and marked", generated, true},
+		{"ordinary column is untouched", plain, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tag := mapper.BuildBunTag(tt.column, nil)
+			parts := strings.Split(tag, ",")
+			has := func(s string) bool {
+				for _, p := range parts {
+					if p == s {
+						return true
+					}
+				}
+				return false
+			}
+			if has("scanonly") != tt.want || has("generated") != tt.want {
+				t.Errorf("tag %q: scanonly/generated present = %v/%v, want %v", tag, has("scanonly"), has("generated"), tt.want)
+			}
+		})
+	}
+}

pkg/writers/bun/identity_column_test.go

@@ -0,0 +1,49 @@
+package bun
+
+import (
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestBuildBunTag_IdentityColumn(t *testing.T) {
+	mapper := NewTypeMapper("", "")
+
+	build := func(pk bool, identity bool, generation string) *models.Column {
+		col := models.InitColumn("id", "users", "public")
+		col.Type = "bigint"
+		col.IsPrimaryKey = pk
+		col.Identity = identity
+		col.IdentityGeneration = generation
+		return col
+	}
+
+	tests := []struct {
+		name       string
+		column     *models.Column
+		wantFlag   bool
+		wantMarker bool
+	}{
+		{"always identity non-pk is write-blocked", build(false, true, "ALWAYS"), true, true},
+		{"always identity pk is only marked", build(true, true, "ALWAYS"), false, true},
+		{"by default identity is writable", build(false, true, "BY DEFAULT"), false, false},
+		{"non-identity is untouched", build(false, false, ""), false, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tag := mapper.BuildBunTag(tt.column, nil)
+			has := func(s string) bool {
+				for _, p := range strings.Split(tag, ",") {
+					if p == s {
+						return true
+					}
+				}
+				return false
+			}
+			if has("scanonly") != tt.wantFlag || has("identity") != tt.wantMarker {
+				t.Errorf("tag %q: scanonly/identity = %v/%v, want %v/%v", tag, has("scanonly"), has("identity"), tt.wantFlag, tt.wantMarker)
+			}
+		})
+	}
+}

pkg/writers/bun/type_mapper.go

@@ -366,6 +366,22 @@ func (tm *TypeMapper) BuildBunTag(column *models.Column, table *models.Table) st
 		parts = append(parts, "autoincrement")
 	}
 
+	// GENERATED ALWAYS ... STORED columns are computed by the database and cannot be
+	// written: scanonly keeps them out of INSERT/UPDATE, generated marks why.
+	if column.Generated {
+		parts = append(parts, "scanonly", "generated")
+	}
+
+	// GENERATED ALWAYS AS IDENTITY rejects explicit values. Bun drops scanonly fields
+	// from the table's PK list, so a primary key only gets the marker; its zero value
+	// is already sent as DEFAULT via autoincrement.
+	if column.Identity && strings.EqualFold(column.IdentityGeneration, "ALWAYS") {
+		if !column.IsPrimaryKey {
+			parts = append(parts, "scanonly")
+		}
+		parts = append(parts, "identity")
+	}
+
 	// Default value
 	if column.Default != nil {
 		// Sanitize default value to remove backticks, then quote based on column type

pkg/writers/dbml/README.md

@@ -111,6 +111,8 @@ Table table_name {
 - `unique` - Unique constraint
 - `default: value` - Default value
 - `note: 'text'` - Column note
+- `note: 'GENERATED ALWAYS AS (expr) STORED'` - Generated column (`Generated`, `GenerationExpression`)
+- `note: 'GENERATED ALWAYS|BY DEFAULT AS IDENTITY'` - Identity column (`Identity`, `IdentityGeneration`)
 
 ### Relationships
 ```dbml

pkg/writers/dbml/generated_columns_test.go

@@ -0,0 +1,77 @@
+package dbml
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+	dbmlreader "git.warky.dev/wdevs/relspecgo/pkg/readers/dbml"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+func TestGeneratedAndIdentityColumnsRoundTrip(t *testing.T) {
+	table := models.InitTable("people", "public")
+
+	id := models.InitColumn("id", "people", "public")
+	id.Type = "bigint"
+	id.IsPrimaryKey = true
+	id.AutoIncrement = true
+	id.Identity = true
+	id.IdentityGeneration = "ALWAYS"
+	table.Columns["id"] = id
+
+	seq := models.InitColumn("seq", "people", "public")
+	seq.Type = "integer"
+	seq.Identity = true
+	seq.IdentityGeneration = "BY DEFAULT"
+	table.Columns["seq"] = seq
+
+	full := models.InitColumn("full_name", "people", "public")
+	full.Type = "text"
+	full.Generated = true
+	full.GenerationExpression = "first || ' ' || last"
+	table.Columns["full_name"] = full
+
+	plain := models.InitColumn("first", "people", "public")
+	plain.Type = "text"
+	plain.Comment = "given name"
+	table.Columns["first"] = plain
+
+	schema := models.InitSchema("public")
+	schema.Tables = append(schema.Tables, table)
+	db := models.InitDatabase("testdb")
+	db.Schemas = append(db.Schemas, schema)
+
+	out := filepath.Join(t.TempDir(), "people.dbml")
+	require.NoError(t, NewWriter(&writers.WriterOptions{OutputPath: out}).WriteDatabase(db))
+
+	content, err := os.ReadFile(out)
+	require.NoError(t, err)
+	assert.Contains(t, string(content), "GENERATED ALWAYS AS (first || \\' \\' || last) STORED")
+	assert.Contains(t, string(content), "GENERATED ALWAYS AS IDENTITY")
+	assert.Contains(t, string(content), "GENERATED BY DEFAULT AS IDENTITY")
+
+	got, err := dbmlreader.NewReader(&readers.ReaderOptions{FilePath: out}).ReadDatabase()
+	require.NoError(t, err)
+	cols := got.Schemas[0].Tables[0].Columns
+
+	assert.True(t, cols["id"].Identity)
+	assert.Equal(t, "ALWAYS", cols["id"].IdentityGeneration)
+	assert.Empty(t, cols["id"].Comment, "marker note must not become a comment")
+
+	assert.True(t, cols["seq"].Identity)
+	assert.Equal(t, "BY DEFAULT", cols["seq"].IdentityGeneration)
+
+	assert.True(t, cols["full_name"].Generated)
+	assert.Equal(t, "first || ' ' || last", cols["full_name"].GenerationExpression)
+	assert.Empty(t, cols["full_name"].Comment)
+
+	assert.False(t, cols["first"].Generated)
+	assert.False(t, cols["first"].Identity)
+	assert.Equal(t, "given name", cols["first"].Comment)
+}

pkg/writers/dbml/writer.go

@@ -114,6 +114,24 @@ func (w *Writer) schemaToDBML(schema *models.Schema) string {
 	return sb.String()
 }
 
+// columnMarkerNote returns the note marking a column the database computes itself
+// (GENERATED ... STORED, or GENERATED ... AS IDENTITY), or "" for an ordinary column.
+// The DBML reader turns the note back into the model's Generated/Identity fields.
+func columnMarkerNote(column *models.Column) string {
+	switch {
+	case column.Generated:
+		return fmt.Sprintf("GENERATED ALWAYS AS (%s) STORED", column.GenerationExpression)
+	case column.Identity && column.IdentityGeneration != "":
+		return fmt.Sprintf("GENERATED %s AS IDENTITY", strings.ToUpper(column.IdentityGeneration))
+	}
+	return ""
+}
+
+// escapeNote escapes a value for use inside a single-quoted DBML note.
+func escapeNote(s string) string {
+	return strings.ReplaceAll(strings.ReplaceAll(s, `\`, `\\`), `'`, `\'`)
+}
+
 // tableToDBML converts a Table to DBML format string
 func (w *Writer) tableToDBML(t *models.Table) string {
 	var sb strings.Builder
@@ -146,6 +164,10 @@ func (w *Writer) tableToDBML(t *models.Table) string {
 			}
 		}
 
+		if marker := columnMarkerNote(column); marker != "" {
+			attrs = append(attrs, fmt.Sprintf("note: '%s'", escapeNote(marker)))
+		}
+
 		if len(attrs) > 0 {
 			fmt.Fprintf(&sb, " [%s]", strings.Join(attrs, ", "))
 		}

pkg/writers/gorm/README.md

@@ -203,6 +203,14 @@ The writer automatically generates relationship fields:
 - Relationship field names use 3-letter prefixes
 - Includes proper `gorm` tags with `foreignKey` and `references`
 
+## Read-only Columns
+
+| Column | Tags |
+|---|---|
+| `GENERATED ... STORED` | `<-:false;generated` |
+| `GENERATED ALWAYS AS IDENTITY`, not PK | `<-:false;identity` |
+| `GENERATED ALWAYS AS IDENTITY`, PK | `identity` only |
+
 ## Notes
 
 - Model names are prefixed with "Model" (e.g., `ModelUser`)

pkg/writers/gorm/generated_column_test.go

@@ -0,0 +1,45 @@
+package gorm
+
+import (
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestBuildGormTag_GeneratedColumn(t *testing.T) {
+	mapper := NewTypeMapper("")
+
+	generated := models.InitColumn("full_name", "users", "public")
+	generated.Type = "text"
+	generated.Generated = true
+
+	plain := models.InitColumn("first", "users", "public")
+	plain.Type = "text"
+
+	tests := []struct {
+		name   string
+		column *models.Column
+		want   bool
+	}{
+		{"generated column is write-disabled and marked", generated, true},
+		{"ordinary column is untouched", plain, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tag := mapper.BuildGormTag(tt.column, nil)
+			parts := strings.Split(tag, ";")
+			has := func(s string) bool {
+				for _, p := range parts {
+					if p == s {
+						return true
+					}
+				}
+				return false
+			}
+			if has("<-:false") != tt.want || has("generated") != tt.want {
+				t.Errorf("tag %q: <-:false/generated present = %v/%v, want %v", tag, has("<-:false"), has("generated"), tt.want)
+			}
+		})
+	}
+}

pkg/writers/gorm/identity_column_test.go

@@ -0,0 +1,49 @@
+package gorm
+
+import (
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestBuildGormTag_IdentityColumn(t *testing.T) {
+	mapper := NewTypeMapper("")
+
+	build := func(pk bool, identity bool, generation string) *models.Column {
+		col := models.InitColumn("id", "users", "public")
+		col.Type = "bigint"
+		col.IsPrimaryKey = pk
+		col.Identity = identity
+		col.IdentityGeneration = generation
+		return col
+	}
+
+	tests := []struct {
+		name       string
+		column     *models.Column
+		wantFlag   bool
+		wantMarker bool
+	}{
+		{"always identity non-pk is write-blocked", build(false, true, "ALWAYS"), true, true},
+		{"always identity pk is only marked", build(true, true, "ALWAYS"), false, true},
+		{"by default identity is writable", build(false, true, "BY DEFAULT"), false, false},
+		{"non-identity is untouched", build(false, false, ""), false, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tag := mapper.BuildGormTag(tt.column, nil)
+			has := func(s string) bool {
+				for _, p := range strings.Split(tag, ";") {
+					if p == s {
+						return true
+					}
+				}
+				return false
+			}
+			if has("<-:false") != tt.wantFlag || has("identity") != tt.wantMarker {
+				t.Errorf("tag %q: <-:false/identity = %v/%v, want %v/%v", tag, has("<-:false"), has("identity"), tt.wantFlag, tt.wantMarker)
+			}
+		})
+	}
+}

pkg/writers/gorm/type_mapper.go

@@ -401,6 +401,21 @@ func (tm *TypeMapper) BuildGormTag(column *models.Column, table *models.Table) s
 		parts = append(parts, "autoIncrement")
 	}
 
+	// GENERATED ALWAYS ... STORED columns are computed by the database and cannot be
+	// written: disable write permission so GORM leaves them out of INSERT/UPDATE, and mark why.
+	if column.Generated {
+		parts = append(parts, "<-:false", "generated")
+	}
+
+	// GENERATED ALWAYS AS IDENTITY rejects explicit values. A primary key only gets the
+	// marker so it keeps its normal create/return behavior.
+	if column.Identity && strings.EqualFold(column.IdentityGeneration, "ALWAYS") {
+		if !column.IsPrimaryKey {
+			parts = append(parts, "<-:false")
+		}
+		parts = append(parts, "identity")
+	}
+
 	// Not null (skip if primary key, as it's implied)
 	if column.NotNull && !column.IsPrimaryKey {
 		parts = append(parts, "not null")

pkg/writers/pgsql/README.md

@@ -164,6 +164,12 @@ When `include_audit` is enabled, adds:
 ## PostgreSQL-Specific Features
 
 - Serial types (SERIAL, BIGSERIAL)
+- Generated columns: `GENERATED ALWAYS AS (expr) STORED` (`Column.Generated` + `GenerationExpression`)
+- Identity columns: `GENERATED ALWAYS|BY DEFAULT AS IDENTITY` (`Column.Identity` + `IdentityGeneration`)
+- Generated/identity columns never carry a `DEFAULT`; emitted in `CREATE TABLE` and `ADD COLUMN` (full DDL and migration)
+- Existing generated/identity columns are not diffed (expression changes are not applied)
+- PK sequence = the `nextval()` default's sequence; `setval` moves it past `MAX(pk)`, forward only
+- `serial`/`bigserial` columns without a model default keep their `nextval()` default in diffs
 - Advanced types (UUID, JSONB, ARRAY)
 - Schema-qualified names
 - Constraint actions (CASCADE, RESTRICT, SET NULL)

pkg/writers/pgsql/generated_column_test.go

@@ -0,0 +1,101 @@
+package pgsql
+
+import (
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+func generationTestTable(withColumns bool) *models.Table {
+	table := models.InitTable("people", "public")
+
+	first := models.InitColumn("first", "people", "public")
+	first.Type = "text"
+	first.Sequence = 1
+	table.Columns["first"] = first
+
+	if !withColumns {
+		return table
+	}
+
+	full := models.InitColumn("full_name", "people", "public")
+	full.Type = "text"
+	full.Sequence = 2
+	full.Generated = true
+	full.GenerationExpression = "first || ' ' || last"
+	full.Default = "ignored"
+	table.Columns["full_name"] = full
+
+	ident := models.InitColumn("seq", "people", "public")
+	ident.Type = "bigint"
+	ident.Sequence = 3
+	ident.NotNull = true
+	ident.Identity = true
+	ident.IdentityGeneration = "ALWAYS"
+	table.Columns["seq"] = ident
+
+	return table
+}
+
+func generationTestDB(table *models.Table) *models.Database {
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+	return db
+}
+
+func TestGeneratedColumns_MigrationCreateAndAddColumn(t *testing.T) {
+	want := []string{
+		"GENERATED ALWAYS AS (first || ' ' || last) STORED",
+		"GENERATED ALWAYS AS IDENTITY",
+	}
+
+	tests := []struct {
+		name    string
+		current *models.Database
+	}{
+		{"new table", models.InitDatabase("testdb")},
+		{"new columns on existing table", generationTestDB(generationTestTable(false))},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			w := NewWriter(&writers.WriterOptions{})
+			stmts, err := w.diffStatements(generationTestDB(generationTestTable(true)), tt.current)
+			if err != nil {
+				t.Fatalf("diffStatements failed: %v", err)
+			}
+			out := diffJoin(stmts)
+			for _, s := range want {
+				if !strings.Contains(out, s) {
+					t.Errorf("missing %q:\n%s", s, out)
+				}
+			}
+			if strings.Contains(out, "DEFAULT ignored") || strings.Contains(out, "DEFAULT 'ignored'") {
+				t.Errorf("generated column must not carry a DEFAULT:\n%s", out)
+			}
+		})
+	}
+}
+
+func TestGeneratedColumns_FullDDL(t *testing.T) {
+	w := NewWriter(&writers.WriterOptions{})
+	stmts, err := w.GenerateDatabaseStatements(generationTestDB(generationTestTable(true)))
+	if err != nil {
+		t.Fatalf("GenerateDatabaseStatements failed: %v", err)
+	}
+	out := diffJoin(stmts)
+	for _, s := range []string{
+		"full_name text GENERATED ALWAYS AS (first || ' ' || last) STORED",
+		"seq bigint GENERATED ALWAYS AS IDENTITY NOT NULL",
+	} {
+		if !strings.Contains(out, s) {
+			t.Errorf("missing %q:\n%s", s, out)
+		}
+	}
+	if strings.Contains(out, "DEFAULT 'ignored'") {
+		t.Errorf("generated column must not carry a DEFAULT:\n%s", out)
+	}
+}

pkg/writers/pgsql/migration_writer.go

@@ -442,6 +442,7 @@ func (w *MigrationWriter) generateAlterTableScripts(schema *models.Schema, model
 		if !exists {
 			// Column doesn't exist, add it
 			_, defaultVal := formatColumnDefaultSQL(modelCol)
+			generated, identity := columnGenerationClauses(modelCol)
 
 			sql, err := w.executor.ExecuteAddColumn(AddColumnData{
 				SchemaName: schema.Name,
@@ -450,6 +451,8 @@ func (w *MigrationWriter) generateAlterTableScripts(schema *models.Schema, model
 				ColumnType: effectiveColumnSQLType(modelCol),
 				Default:    defaultVal,
 				NotNull:    modelCol.NotNull,
+				Generated:  generated,
+				Identity:   identity,
 			})
 			if err != nil {
 				return nil, err

pkg/writers/pgsql/templates.go

@@ -77,6 +77,10 @@ type ColumnData struct {
 	Type    string
 	Default string
 	NotNull bool
+	// Generated is the expression of a GENERATED ALWAYS AS (...) STORED column.
+	Generated string
+	// Identity is "ALWAYS" or "BY DEFAULT" for a GENERATED ... AS IDENTITY column.
+	Identity string
 }
 
 // AddColumnData contains data for add column template
@@ -87,6 +91,10 @@ type AddColumnData struct {
 	ColumnType string
 	Default    string
 	NotNull    bool
+	// Generated is the expression of a GENERATED ALWAYS AS (...) STORED column.
+	Generated string
+	// Identity is "ALWAYS" or "BY DEFAULT" for a GENERATED ... AS IDENTITY column.
+	Identity string
 }
 
 // AlterColumnTypeWithCheckData contains data for the guarded alter column
@@ -520,6 +528,19 @@ func (te *TemplateExecutor) ExecuteCreatePrimaryKeyWithAutoGenCheck(data CreateP
 
 // Helper functions to build template data from models
 
+// columnGenerationClauses returns the generation expression of a GENERATED ... STORED
+// column and the generation mode of an identity column ("" for each that does not apply).
+// Such columns cannot carry a DEFAULT.
+func columnGenerationClauses(col *models.Column) (generated, identity string) {
+	if col.Generated && col.GenerationExpression != "" {
+		return col.GenerationExpression, ""
+	}
+	if col.Identity && col.IdentityGeneration != "" {
+		return "", strings.ToUpper(col.IdentityGeneration)
+	}
+	return "", ""
+}
+
 // BuildCreateTableData builds CreateTableData from a models.Table
 func BuildCreateTableData(schemaName string, table *models.Table) CreateTableData {
 	columns := make([]ColumnData, 0, len(table.Columns))
@@ -532,7 +553,8 @@ func BuildCreateTableData(schemaName string, table *models.Table) CreateTableDat
 			Type:    col.Type,
 			NotNull: col.NotNull,
 		}
-		if col.Default != nil {
+		colData.Generated, colData.Identity = columnGenerationClauses(col)
+		if col.Default != nil && colData.Generated == "" && colData.Identity == "" {
 			if value, ok := col.Default.(string); ok {
 				colData.Default = writers.QuoteDefaultValue(stripBackticks(value), col.Type)
 			} else {

pkg/writers/pgsql/templates/add_column.tmpl

@@ -1,4 +1,6 @@
 ALTER TABLE {{qual_table .SchemaName .TableName}}
   ADD COLUMN IF NOT EXISTS {{quote_ident .ColumnName}} {{.ColumnType}}
-{{- if .Default}} DEFAULT {{.Default}}{{end}}
+{{- if .Generated}} GENERATED ALWAYS AS ({{.Generated}}) STORED{{end}}
+{{- if .Identity}} GENERATED {{.Identity}} AS IDENTITY{{end}}
+{{- if and .Default (not .Generated) (not .Identity)}} DEFAULT {{.Default}}{{end}}
 {{- if .NotNull}} NOT NULL{{end}};

pkg/writers/pgsql/templates/create_table.tmpl

@@ -2,7 +2,9 @@ CREATE TABLE IF NOT EXISTS {{qual_table .SchemaName .TableName}} (
 {{- range $i, $col := .Columns}}
 {{- if $i}},{{end}}
   {{quote_ident $col.Name}} {{$col.Type}}
-{{- if $col.Default}} DEFAULT {{$col.Default}}{{end}}
+{{- if $col.Generated}} GENERATED ALWAYS AS ({{$col.Generated}}) STORED{{end}}
+{{- if $col.Identity}} GENERATED {{$col.Identity}} AS IDENTITY{{end}}
+{{- if and $col.Default (not $col.Generated) (not $col.Identity)}} DEFAULT {{$col.Default}}{{end}}
 {{- if $col.NotNull}} NOT NULL{{end}}
 {{- end}}
 );

pkg/writers/pgsql/templates/fragments.tmpl

@@ -3,7 +3,9 @@
 {{/* Column definition fragment */}}
 {{- define "column_definition" -}}
 {{.Name}} {{.Type}}
-{{- if .Default}} DEFAULT {{.Default}}{{end}}
+{{- if .Generated}} GENERATED ALWAYS AS ({{.Generated}}) STORED{{end}}
+{{- if .Identity}} GENERATED {{.Identity}} AS IDENTITY{{end}}
+{{- if and .Default (not .Generated) (not .Identity)}} DEFAULT {{.Default}}{{end}}
 {{- if .NotNull}} NOT NULL{{end}}
 {{- end -}}