chore: 可根据 driver 自动设置 Dialect

gdb/orm/orm.go

@@ -38,6 +38,9 @@ type ConnectionConfig struct {
 	// just remember that having a connection name is mandatory if
 	// you have multiple connections
 	Name string
+
+	// 不是必需，不指定 Dialect 时必需
+	Driver string
 	// If you already have an active database connection configured pass it in this value and
 	// do not pass Driver and DSN fields.
 	DB *sql.DB
@@ -77,6 +80,18 @@ func NewDb(opt DbOption) (*sql.DB, error) {
 	return db, nil
 }
 
+func getDialectByDriver(driver string) (*Dialect, error) {
+	switch driver {
+	case "postgres":
+		return Dialects.PostgreSQL, nil
+	case "mysql":
+		return Dialects.MySQL, nil
+	case "sqlite3":
+		return Dialects.SQLite3, nil
+	}
+	return nil, fmt.Errorf("unsupported db driver %s", driver)
+}
+
 // SetupConnections declares a new connections for ORM.
 func SetupConnections(configs ...ConnectionConfig) error {
 
@@ -132,6 +147,13 @@ func setupConnection(config ConnectionConfig) error {
 	if config.Name == "" {
 		config.Name = "default"
 	}
+	if config.Dialect == nil {
+		dialect, err := getDialectByDriver(config.Driver)
+		if err != nil {
+			return err
+		}
+		config.Dialect = dialect
+	}
 
 	for _, entity := range config.Entities {
 		s := schemaOfHeavyReflectionStuff(entity)