feat: generated and identity columns for mssql, sqlite, drizzle, typeorm, bun and gorm readers

- mssql: write computed columns (AS (expr) PERSISTED) and identity; read computed definition and identity
- sqlite: write GENERATED ALWAYS AS (expr) STORED; read generated columns via table_xinfo and parse the expression
- drizzle: generatedAlwaysAs / generated(Always|ByDefault)AsIdentity, read and write
- typeorm: asExpression/generatedType and identity decorators, read and write; decorator scan is now quote-aware
- bun, gorm readers: read generated and identity markers
- readmes updated

pkg/readers/gorm/README.md

@@ -78,6 +78,8 @@ The reader recognizes the following GORM struct tags:
 - `not null` - NOT NULL constraint
 - `autoIncrement` - Auto-increment column
 - `default` - Default value
+- `generated` - Generated column marker (`Generated`; expression is not in the tag)
+- `identity` - Identity column marker (`Identity`, `ALWAYS`)
 - `size` - Column size/length
 - `index` - Create index
 - `uniqueIndex` - Create unique index

pkg/readers/gorm/generated_column_test.go

@@ -0,0 +1,48 @@
+package gorm
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+)
+
+func TestReader_GeneratedAndIdentityMarkers(t *testing.T) {
+	src := `package models
+
+type Person struct {
+	ID       int64  ` + "`gorm:\"column:id;primaryKey;autoIncrement;type:bigint;identity\"`" + `
+	Seq      int64  ` + "`gorm:\"column:seq;type:bigint;<-:false;identity;not null\"`" + `
+	FullName string ` + "`gorm:\"column:full_name;type:text;<-:false;generated\"`" + `
+	First    string ` + "`gorm:\"column:first;type:text\"`" + `
+}
+
+func (Person) TableName() string {
+	return "people"
+}
+`
+	path := filepath.Join(t.TempDir(), "person.go")
+	if err := os.WriteFile(path, []byte(src), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	db, err := NewReader(&readers.ReaderOptions{FilePath: path}).ReadDatabase()
+	if err != nil {
+		t.Fatalf("ReadDatabase() error = %v", err)
+	}
+	cols := db.Schemas[0].Tables[0].Columns
+
+	if !cols["id"].Identity || cols["id"].IdentityGeneration != "ALWAYS" {
+		t.Errorf("id: identity = %v/%q, want true/ALWAYS", cols["id"].Identity, cols["id"].IdentityGeneration)
+	}
+	if !cols["seq"].Identity {
+		t.Error("seq should be identity")
+	}
+	if !cols["full_name"].Generated {
+		t.Error("full_name should be generated")
+	}
+	if cols["first"].Generated || cols["first"].Identity {
+		t.Error("first must be an ordinary column")
+	}
+}

pkg/readers/gorm/reader.go

@@ -726,6 +726,15 @@ func (r *Reader) parseColumn(fieldName string, fieldType ast.Expr, tag string, s
 	if _, ok := parts["autoincrement"]; ok {
 		column.AutoIncrement = true
 	}
+	if _, ok := parts["generated"]; ok {
+		// GENERATED ... STORED marker written by the GORM writer; the expression is not in the tag
+		column.Generated = true
+	}
+	if _, ok := parts["identity"]; ok {
+		// GENERATED ALWAYS AS IDENTITY marker written by the GORM writer
+		column.Identity = true
+		column.IdentityGeneration = "ALWAYS"
+	}
 	if def, ok := parts["default"]; ok {
 		// Default value from GORM tag (e.g., default:gen_random_uuid())
 		column.Default = def