feat: support disable dialect's feature

At the same time, we have also consolidated the logic
for determining features in the database into the dialect.

db.go

@@ -35,8 +35,7 @@ func WithDiscardUnknownColumns() DBOption {
 type DB struct {
 	*sql.DB
 
-	dialect  schema.Dialect
-	features feature.Feature
+	dialect schema.Dialect
 
 	queryHooks []QueryHook
 
@@ -50,10 +49,9 @@ func NewDB(sqldb *sql.DB, dialect schema.Dialect, opts ...DBOption) *DB {
 	dialect.Init(sqldb)
 
 	db := &DB{
-		DB:       sqldb,
-		dialect:  dialect,
-		features: dialect.Features(),
-		fmter:    schema.NewFormatter(dialect),
+		DB:      sqldb,
+		dialect: dialect,
+		fmter:   schema.NewFormatter(dialect),
 	}
 
 	for _, opt := range opts {
@@ -231,7 +229,7 @@ func (db *DB) UpdateFQN(alias, column string) Ident {
 
 // HasFeature uses feature package to report whether the underlying DBMS supports this feature.
 func (db *DB) HasFeature(feat feature.Feature) bool {
-	return db.fmter.HasFeature(feat)
+	return db.dialect.Features().Has(feat)
 }
 
 //------------------------------------------------------------------------------
@@ -513,7 +511,7 @@ func (tx Tx) commitTX() error {
 }
 
 func (tx Tx) commitSP() error {
-	if tx.Dialect().Features().Has(feature.MSSavepoint) {
+	if tx.db.HasFeature(feature.MSSavepoint) {
 		return nil
 	}
 	query := "RELEASE SAVEPOINT " + tx.name
@@ -537,7 +535,7 @@ func (tx Tx) rollbackTX() error {
 
 func (tx Tx) rollbackSP() error {
 	query := "ROLLBACK TO SAVEPOINT " + tx.name
-	if tx.Dialect().Features().Has(feature.MSSavepoint) {
+	if tx.db.HasFeature(feature.MSSavepoint) {
 		query = "ROLLBACK TRANSACTION " + tx.name
 	}
 	_, err := tx.ExecContext(tx.ctx, query)
@@ -601,7 +599,7 @@ func (tx Tx) BeginTx(ctx context.Context, _ *sql.TxOptions) (Tx, error) {
 
 	qName := "SP_" + hex.EncodeToString(sp)
 	query := "SAVEPOINT " + qName
-	if tx.Dialect().Features().Has(feature.MSSavepoint) {
+	if tx.db.HasFeature(feature.MSSavepoint) {
 		query = "SAVE TRANSACTION " + qName
 	}
 	_, err = tx.ExecContext(ctx, query)

dialect/mssqldialect/dialect.go

@@ -39,7 +39,7 @@ type Dialect struct {
 	features feature.Feature
 }
 
-func New() *Dialect {
+func New(opts ...DialectOption) *Dialect {
 	d := new(Dialect)
 	d.tables = schema.NewTables(d)
 	d.features = feature.CTE |
@@ -49,9 +49,21 @@ func New() *Dialect {
 		feature.OffsetFetch |
 		feature.UpdateFromTable |
 		feature.MSSavepoint
+
+	for _, opt := range opts {
+		opt(d)
+	}
 	return d
 }
 
+type DialectOption func(d *Dialect)
+
+func RemoveFeature(other feature.Feature) DialectOption {
+	return func(d *Dialect) {
+		d.features = d.features.Remove(other)
+	}
+}
+
 func (d *Dialect) Init(db *sql.DB) {
 	var version string
 	if err := db.QueryRow("SELECT @@VERSION").Scan(&version); err != nil {

dialect/mysqldialect/dialect.go

@@ -27,8 +27,6 @@ func init() {
 	}
 }
 
-type DialectOption func(d *Dialect)
-
 type Dialect struct {
 	schema.BaseDialect
 
@@ -60,6 +58,8 @@ func New(opts ...DialectOption) *Dialect {
 	return d
 }
 
+type DialectOption func(d *Dialect)
+
 func WithTimeLocation(loc string) DialectOption {
 	return func(d *Dialect) {
 		location, err := time.LoadLocation(loc)
@@ -70,6 +70,12 @@ func WithTimeLocation(loc string) DialectOption {
 	}
 }
 
+func RemoveFeature(other feature.Feature) DialectOption {
+	return func(d *Dialect) {
+		d.features = d.features.Remove(other)
+	}
+}
+
 func (d *Dialect) Init(db *sql.DB) {
 	var version string
 	if err := db.QueryRow("SELECT version()").Scan(&version); err != nil {

dialect/oracledialect/dialect.go

@@ -27,7 +27,7 @@ type Dialect struct {
 	features feature.Feature
 }
 
-func New() *Dialect {
+func New(opts ...DialectOption) *Dialect {
 	d := new(Dialect)
 	d.tables = schema.NewTables(d)
 	d.features = feature.CTE |
@@ -42,9 +42,22 @@ func New() *Dialect {
 		feature.AutoIncrement |
 		feature.CompositeIn |
 		feature.DeleteReturning
+
+	for _, opt := range opts {
+		opt(d)
+	}
+
 	return d
 }
 
+type DialectOption func(d *Dialect)
+
+func RemoveFeature(other feature.Feature) DialectOption {
+	return func(d *Dialect) {
+		d.features = d.features.Remove(other)
+	}
+}
+
 func (d *Dialect) Init(*sql.DB) {}
 
 func (d *Dialect) Name() dialect.Name {

dialect/pgdialect/dialect.go

@@ -34,7 +34,7 @@ var _ schema.Dialect = (*Dialect)(nil)
 var _ sqlschema.InspectorDialect = (*Dialect)(nil)
 var _ sqlschema.MigratorDialect = (*Dialect)(nil)
 
-func New() *Dialect {
+func New(opts ...DialectOption) *Dialect {
 	d := new(Dialect)
 	d.tables = schema.NewTables(d)
 	d.features = feature.CTE |
@@ -55,9 +55,22 @@ func New() *Dialect {
 		feature.GeneratedIdentity |
 		feature.CompositeIn |
 		feature.DeleteReturning
+
+	for _, opt := range opts {
+		opt(d)
+	}
+
 	return d
 }
 
+type DialectOption func(d *Dialect)
+
+func RemoveFeature(other feature.Feature) DialectOption {
+	return func(d *Dialect) {
+		d.features = d.features.Remove(other)
+	}
+}
+
 func (d *Dialect) Init(*sql.DB) {}
 
 func (d *Dialect) Name() dialect.Name {

dialect/sqlitedialect/dialect.go

@@ -26,7 +26,7 @@ type Dialect struct {
 	features feature.Feature
 }
 
-func New() *Dialect {
+func New(opts ...DialectOption) *Dialect {
 	d := new(Dialect)
 	d.tables = schema.NewTables(d)
 	d.features = feature.CTE |
@@ -42,9 +42,22 @@ func New() *Dialect {
 		feature.AutoIncrement |
 		feature.CompositeIn |
 		feature.DeleteReturning
+
+	for _, opt := range opts {
+		opt(d)
+	}
+
 	return d
 }
 
+type DialectOption func(d *Dialect)
+
+func RemoveFeature(other feature.Feature) DialectOption {
+	return func(d *Dialect) {
+		d.features = d.features.Remove(other)
+	}
+}
+
 func (d *Dialect) Init(*sql.DB) {}
 
 func (d *Dialect) Name() dialect.Name {

model_map_slice.go

@@ -99,7 +99,7 @@ func (m *mapSliceModel) appendValues(fmter schema.Formatter, b []byte) (_ []byte
 	slice := *m.dest
 
 	b = append(b, "VALUES "...)
-	if m.db.features.Has(feature.ValuesRow) {
+	if m.db.HasFeature(feature.ValuesRow) {
 		b = append(b, "ROW("...)
 	} else {
 		b = append(b, '(')
@@ -118,7 +118,7 @@ func (m *mapSliceModel) appendValues(fmter schema.Formatter, b []byte) (_ []byte
 	for i, el := range slice {
 		if i > 0 {
 			b = append(b, "), "...)
-			if m.db.features.Has(feature.ValuesRow) {
+			if m.db.HasFeature(feature.ValuesRow) {
 				b = append(b, "ROW("...)
 			} else {
 				b = append(b, '(')

query_base.go

@@ -201,7 +201,7 @@ func (q *baseQuery) beforeAppendModel(ctx context.Context, query Query) error {
 }
 
 func (q *baseQuery) hasFeature(feature feature.Feature) bool {
-	return q.db.features.Has(feature)
+	return q.db.HasFeature(feature)
 }
 
 //------------------------------------------------------------------------------

query_delete.go

@@ -201,7 +201,7 @@ func (q *DeleteQuery) AppendQuery(fmter schema.Formatter, b []byte) (_ []byte, e
 		return upd.AppendQuery(fmter, b)
 	}
 
-	withAlias := q.db.features.Has(feature.DeleteTableAlias)
+	withAlias := q.db.HasFeature(feature.DeleteTableAlias)
 
 	b, err = q.appendWith(fmter, b)
 	if err != nil {

query_insert.go

@@ -190,7 +190,7 @@ func (q *InsertQuery) AppendQuery(fmter schema.Formatter, b []byte) (_ []byte, e
 	}
 	b = append(b, "INTO "...)
 
-	if q.db.features.Has(feature.InsertTableAlias) && !q.on.IsZero() {
+	if q.db.HasFeature(feature.InsertTableAlias) && !q.on.IsZero() {
 		b, err = q.appendFirstTableWithAlias(fmter, b)
 	} else {
 		b, err = q.appendFirstTable(fmter, b)
@@ -385,9 +385,9 @@ func (q *InsertQuery) appendSliceValues(
 }
 
 func (q *InsertQuery) getFields() ([]*schema.Field, error) {
-	hasIdentity := q.db.features.Has(feature.Identity)
+	hasIdentity := q.db.HasFeature(feature.Identity)
 
-	if len(q.columns) > 0 || q.db.features.Has(feature.DefaultPlaceholder) && !hasIdentity {
+	if len(q.columns) > 0 || q.db.HasFeature(feature.DefaultPlaceholder) && !hasIdentity {
 		return q.baseQuery.getFields()
 	}
 
@@ -640,8 +640,8 @@ func (q *InsertQuery) afterInsertHook(ctx context.Context) error {
 }
 
 func (q *InsertQuery) tryLastInsertID(res sql.Result, dest []interface{}) error {
-	if q.db.features.Has(feature.Returning) ||
-		q.db.features.Has(feature.Output) ||
+	if q.db.HasFeature(feature.Returning) ||
+		q.db.HasFeature(feature.Output) ||
 		q.table == nil ||
 		len(q.table.PKs) != 1 ||
 		!q.table.PKs[0].AutoIncrement {

query_table_truncate.go

@@ -110,7 +110,7 @@ func (q *TruncateTableQuery) AppendQuery(
 		return nil, err
 	}
 
-	if q.db.features.Has(feature.TableIdentity) {
+	if q.db.HasFeature(feature.TableIdentity) {
 		if q.continueIdentity {
 			b = append(b, " CONTINUE IDENTITY"...)
 		} else {

query_values.go

@@ -145,7 +145,7 @@ func (q *ValuesQuery) appendQuery(
 	fields []*schema.Field,
 ) (_ []byte, err error) {
 	b = append(b, "VALUES "...)
-	if q.db.features.Has(feature.ValuesRow) {
+	if q.db.HasFeature(feature.ValuesRow) {
 		b = append(b, "ROW("...)
 	} else {
 		b = append(b, '(')
@@ -168,7 +168,7 @@ func (q *ValuesQuery) appendQuery(
 		for i := 0; i < sliceLen; i++ {
 			if i > 0 {
 				b = append(b, "), "...)
-				if q.db.features.Has(feature.ValuesRow) {
+				if q.db.HasFeature(feature.ValuesRow) {
 					b = append(b, "ROW("...)
 				} else {
 					b = append(b, '(')

relation_join.go

@@ -63,7 +63,7 @@ func (j *relationJoin) manyQuery(q *SelectQuery) *SelectQuery {
 
 	var where []byte
 
-	if q.db.dialect.Features().Has(feature.CompositeIn) {
+	if q.db.HasFeature(feature.CompositeIn) {
 		return j.manyQueryCompositeIn(where, q)
 	}
 	return j.manyQueryMulti(where, q)