feat(writer): 🎉 Improve primary key handling by checking for explicit constraints and columns

pkg/writers/pgsql/migration_writer.go

@@ -427,9 +427,11 @@ func (w *MigrationWriter) generateIndexScripts(model *models.Schema, current *mo
 	for _, modelTable := range model.Tables {
 		currentTable := currentTables[strings.ToLower(modelTable.Name)]
 
-		// Process primary keys first
+		// Process primary keys first - check explicit constraints
+		foundExplicitPK := false
 		for constraintName, constraint := range modelTable.Constraints {
 			if constraint.Type == models.PrimaryKeyConstraint {
+				foundExplicitPK = true
 				shouldCreate := true
 
 				if currentTable != nil {
@@ -464,6 +466,53 @@ func (w *MigrationWriter) generateIndexScripts(model *models.Schema, current *mo
 			}
 		}
 
+		// If no explicit PK constraint, check for columns with IsPrimaryKey = true
+		if !foundExplicitPK {
+			pkColumns := []string{}
+			for _, col := range modelTable.Columns {
+				if col.IsPrimaryKey {
+					pkColumns = append(pkColumns, col.SQLName())
+				}
+			}
+			if len(pkColumns) > 0 {
+				sort.Strings(pkColumns)
+				constraintName := fmt.Sprintf("pk_%s_%s", strings.ToLower(model.Name), strings.ToLower(modelTable.Name))
+				shouldCreate := true
+
+				if currentTable != nil {
+					// Check if a PK constraint already exists (by any name)
+					for _, constraint := range currentTable.Constraints {
+						if constraint.Type == models.PrimaryKeyConstraint {
+							shouldCreate = false
+							break
+						}
+					}
+				}
+
+				if shouldCreate {
+					sql, err := w.executor.ExecuteCreatePrimaryKey(CreatePrimaryKeyData{
+						SchemaName:     model.Name,
+						TableName:      modelTable.Name,
+						ConstraintName: constraintName,
+						Columns:        strings.Join(pkColumns, ", "),
+					})
+					if err != nil {
+						return nil, err
+					}
+
+					script := MigrationScript{
+						ObjectName: fmt.Sprintf("%s.%s.%s", model.Name, modelTable.Name, constraintName),
+						ObjectType: "create primary key",
+						Schema:     model.Name,
+						Priority:   160,
+						Sequence:   len(scripts),
+						Body:       sql,
+					}
+					scripts = append(scripts, script)
+				}
+			}
+		}
+
 		// Process indexes
 		for indexName, modelIndex := range modelTable.Indexes {
 			// Skip primary key indexes