diff --git a/delete.go b/delete.go
index b339591..592f487 100644
--- a/delete.go
+++ b/delete.go
@@ -1,15 +1,13 @@
 package sqimple
 
 import (
-	"context"
 	"database/sql"
 	"strings"
 )
 
 // https://www.sqlite.org/lang_delete.html
 type DeleteStatement struct {
-	Ctx context.Context
-	DB  *sql.DB
+	execFunc func(Query) (sql.Result, error)
 
 	table SelectTable
 
@@ -22,15 +20,16 @@ func (s *DeleteStatement) Args() []any {
 }
 
 func (s *DeleteStatement) Exec() (sql.Result, error) {
-	if s.DB != nil {
-		if s.Ctx != nil {
-			return s.DB.ExecContext(s.Ctx, s.String(), s.Args()...)
-		}
-
-		return s.DB.Exec(s.String(), s.Args()...)
+	if s.execFunc != nil {
+		return s.execFunc(s)
 	}
 
-	return nil, ErrNoDatabase
+	return nil, nil
+}
+
+func (s *DeleteStatement) ExecFunc(f func(Query) (sql.Result, error)) *DeleteStatement {
+	s.execFunc = f
+	return s
 }
 
 func (s *DeleteStatement) IsValid() bool {
diff --git a/insert.go b/insert.go
index 768e6b8..a9c3683 100644
--- a/insert.go
+++ b/insert.go
@@ -1,7 +1,6 @@
 package sqimple
 
 import (
-	"context"
 	"database/sql"
 	"fmt"
 	"slices"
@@ -10,8 +9,7 @@ import (
 
 // https://www.sqlite.org/lang_delete.html
 type InsertStatement struct {
-	Ctx context.Context
-	DB  *sql.DB
+	execFunc func(Query) (sql.Result, error)
 
 	table InsertTable
 	or    string
@@ -38,15 +36,16 @@ func (s *InsertStatement) Args() []any {
 }
 
 func (s *InsertStatement) Exec() (sql.Result, error) {
-	if s.DB != nil {
-		if s.Ctx != nil {
-			return s.DB.ExecContext(s.Ctx, s.String(), s.Args()...)
-		}
-
-		return s.DB.Exec(s.String(), s.Args()...)
+	if s.execFunc != nil {
+		return s.execFunc(s)
 	}
 
-	return nil, ErrNoDatabase
+	return nil, nil
+}
+
+func (s *InsertStatement) ExecFunc(f func(Query) (sql.Result, error)) *InsertStatement {
+	s.execFunc = f
+	return s
 }
 
 func (s *InsertStatement) IsValid() bool {
diff --git a/select.go b/select.go
index ff3b3a6..daaa682 100644
--- a/select.go
+++ b/select.go
@@ -11,8 +11,11 @@ import (
 
 // https://www.sqlite.org/lang_select.html
 type SelectQuery struct {
-	Ctx context.Context
-	DB  *sql.DB
+	ctx context.Context
+	db  *sql.DB
+
+	queryFunc    func(Query) (*sql.Rows, error)
+	queryRowFunc func(Query) *sql.Row
 
 	distinct bool
 
@@ -48,6 +51,16 @@ func (q *SelectQuery) Columns(defs ...string) *SelectQuery {
 	return q
 }
 
+func (q *SelectQuery) Ctx(ctx context.Context) *SelectQuery {
+	q.ctx = ctx
+	return q
+}
+
+func (q *SelectQuery) DB(db *sql.DB) *SelectQuery {
+	q.db = db
+	return q
+}
+
 func (q *SelectQuery) Distinct(distinct bool) *SelectQuery {
 	q.distinct = distinct
 
@@ -114,15 +127,16 @@ func (q *SelectQuery) OrderBy(defs ...string) *SelectQuery {
 }
 
 func (q *SelectQuery) Query() (*sql.Rows, error) {
-	if q.DB != nil {
-		if q.Ctx != nil {
-			return q.DB.QueryContext(q.Ctx, q.String(), q.Args()...)
-		}
-
-		return q.DB.Query(q.String(), q.Args()...)
+	if q.queryFunc != nil {
+		return q.queryFunc(q)
 	}
 
-	return nil, ErrNoDatabase
+	return nil, nil
+}
+
+func (q *SelectQuery) QueryFunc(f func(Query) (*sql.Rows, error)) *SelectQuery {
+	q.queryFunc = f
+	return q
 }
 
 func (q *SelectQuery) QueryRecord() (record.Record, error) {
@@ -144,17 +158,18 @@ func (q *SelectQuery) QueryRecords() ([]record.Record, error) {
 }
 
 func (q *SelectQuery) QueryRow() *sql.Row {
-	if q.DB != nil {
-		if q.Ctx != nil {
-			return q.DB.QueryRowContext(q.Ctx, q.String(), q.Args()...)
-		}
-
-		return q.DB.QueryRow(q.String(), q.Args()...)
+	if q.queryRowFunc != nil {
+		return q.queryRowFunc(q)
 	}
 
 	return nil
 }
 
+func (q *SelectQuery) QueryRowFunc(f func(Query) *sql.Row) *SelectQuery {
+	q.queryRowFunc = f
+	return q
+}
+
 func (q *SelectQuery) String() string {
 	strs := []string{"select"}
 
diff --git a/update.go b/update.go
index afa3d64..00073ef 100644
--- a/update.go
+++ b/update.go
@@ -1,7 +1,6 @@
 package sqimple
 
 import (
-	"context"
 	"database/sql"
 	"slices"
 	"strings"
@@ -9,8 +8,7 @@ import (
 
 // https://www.sqlite.org/lang_update.html
 type UpdateStatement struct {
-	Ctx context.Context
-	DB  *sql.DB
+	execFunc func(Query) (sql.Result, error)
 
 	table UpdateTable
 	or    string
@@ -37,15 +35,16 @@ func (s *UpdateStatement) Args() []any {
 }
 
 func (s *UpdateStatement) Exec() (sql.Result, error) {
-	if s.DB != nil {
-		if s.Ctx != nil {
-			return s.DB.ExecContext(s.Ctx, s.String(), s.Args()...)
-		}
-
-		return s.DB.Exec(s.String(), s.Args()...)
+	if s.execFunc != nil {
+		return s.execFunc(s)
 	}
 
-	return nil, ErrNoDatabase
+	return nil, nil
+}
+
+func (s *UpdateStatement) ExecFunc(f func(Query) (sql.Result, error)) *UpdateStatement {
+	s.execFunc = f
+	return s
 }
 
 func (s *UpdateStatement) IsValid() bool {