fix(migrator): add missing helper functions for v0.4.1

- Add isAlreadyExistsError() function for consistent error detection
- Add isAutoIncrementField() method for proper field identification
- Improve migration robustness and DuckDB compatibility
- Update CHANGELOG.md for v0.4.1 patch release

These helper functions enhance migration reliability by providing
better error handling and auto-increment field detection.

Author: greysquirr3l

CHANGELOG.md

@@ -7,6 +7,25 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.4.1] - 2025-08-20
+
+### 🔧 Fixed
+
+- **Migrator Helper Functions**: Added missing helper functions for improved migration reliability
+  - `isAlreadyExistsError()`: Checks if an error indicates object already exists (handles "already exists" and "duplicate" error patterns)
+  - `isAutoIncrementField()`: Identifies auto-increment fields for proper sequence handling
+- **Code Organization**: Better separation of concerns in migrator functionality
+
+### 🛠️ Technical Details
+
+The helper functions improve migration robustness by:
+
+- **Error Handling**: Consistent detection of duplicate object creation attempts
+- **Auto-increment Detection**: Proper identification of fields requiring sequence-based auto-increment behavior
+- **DuckDB Compatibility**: Enhanced support for DuckDB-specific migration patterns
+
+These changes maintain full backward compatibility while improving internal migration logic.
+
 ## [0.4.0] - 2025-08-14
 
 ### 🚀 Comprehensive Extension Management & Test Coverage Revolution

migrator.go

@@ -16,11 +16,26 @@ const (
 	sqlTypeInteger = "INTEGER"
 )
 
+// isAlreadyExistsError checks if an error indicates that an object already exists
+func isAlreadyExistsError(err error) bool {
+	if err == nil {
+		return false
+	}
+	errMsg := strings.ToLower(err.Error())
+	return strings.Contains(errMsg, "already exists") ||
+		strings.Contains(errMsg, "duplicate")
+}
+
 // Migrator implements gorm.Migrator interface for DuckDB database.
 type Migrator struct {
 	migrator.Migrator
 }
 
+// isAutoIncrementField checks if a field is an auto-increment field
+func (m Migrator) isAutoIncrementField(field *schema.Field) bool {
+	return field.AutoIncrement || (!field.HasDefaultValue && field.DataType == schema.Uint)
+}
+
 // CurrentDatabase returns the current database name.
 func (m Migrator) CurrentDatabase() (name string) {
 	_ = m.DB.Raw("SELECT current_database()").Row().Scan(&name)