diff --git a/base.go b/base.go
index ce5346c7..985ea46d 100644
--- a/base.go
+++ b/base.go
@@ -524,11 +524,11 @@ func (db *baseDB) Ping(ctx context.Context) error {
 }
 
 // Model returns new query for the model.
-func (db *baseDB) Model(model ...interface{}) *orm.Query {
+func (db *baseDB) Model(model ...interface{}) *Query {
 	return orm.NewQuery(db.db, model...)
 }
 
-func (db *baseDB) ModelContext(c context.Context, model ...interface{}) *orm.Query {
+func (db *baseDB) ModelContext(c context.Context, model ...interface{}) *Query {
 	return orm.NewQueryContext(c, db.db, model...)
 }
 
diff --git a/db_test.go b/db_test.go
index ee9562b2..d941a33b 100644
--- a/db_test.go
+++ b/db_test.go
@@ -1394,10 +1394,10 @@ var _ = Describe("ORM", func() {
 				Relation("Editor.Avatar").
 				Relation("Genres").
 				Relation("Comments").
-				Relation("Translations", func(q *orm.Query) (*orm.Query, error) {
+				Relation("Translations", func(q *pg.Query) (*pg.Query, error) {
 					return q.Order("id"), nil
 				}).
-				Relation("Translations.Comments", func(q *orm.Query) (*orm.Query, error) {
+				Relation("Translations.Comments", func(q *pg.Query) (*pg.Query, error) {
 					return q.Order("text"), nil
 				}).
 				First()
@@ -2074,7 +2074,7 @@ var _ = Describe("ORM", func() {
 		var book Book
 		err := db.Model(&book).
 			Column("book.id").
-			Relation("Translations", func(q *orm.Query) (*orm.Query, error) {
+			Relation("Translations", func(q *pg.Query) (*pg.Query, error) {
 				return q.Where("lang = 'ru'"), nil
 			}).
 			First()
@@ -2091,7 +2091,7 @@ var _ = Describe("ORM", func() {
 		var book Book
 		err := db.Model(&book).
 			Column("book.id").
-			Relation("Genres", func(q *orm.Query) (*orm.Query, error) {
+			Relation("Genres", func(q *pg.Query) (*pg.Query, error) {
 				return q.Where("genre__rating > 999"), nil
 			}).
 			First()
diff --git a/example_many2many_test.go b/example_many2many_test.go
index 62052e93..b3a25528 100644
--- a/example_many2many_test.go
+++ b/example_many2many_test.go
@@ -75,7 +75,7 @@ func ExampleDB_Model_manyToMany() {
 
 	order = new(Order)
 	err = db.Model(order).
-		Relation("Items", func(q *orm.Query) (*orm.Query, error) {
+		Relation("Items", func(q *pg.Query) (*pg.Query, error) {
 			q = q.OrderExpr("item.id DESC")
 			return q, nil
 		}).
diff --git a/example_model_test.go b/example_model_test.go
index 7fe4e4a2..0e664933 100644
--- a/example_model_test.go
+++ b/example_model_test.go
@@ -351,7 +351,7 @@ func ExampleDB_Model_selectWhereGroup() {
 
 	var books []Book
 	err := db.Model(&books).
-		WhereGroup(func(q *orm.Query) (*orm.Query, error) {
+		WhereGroup(func(q *pg.Query) (*pg.Query, error) {
 			q = q.WhereOr("id = 1").
 				WhereOr("id = 2")
 			return q, nil
@@ -443,7 +443,7 @@ func ExampleDB_Model_selectApplyFunc() {
 	var authorId int
 	var editorId int
 
-	filter := func(q *orm.Query) (*orm.Query, error) {
+	filter := func(q *pg.Query) (*pg.Query, error) {
 		if authorId != 0 {
 			q = q.Where("author_id = ?", authorId)
 		}
@@ -700,7 +700,7 @@ func ExampleDB_Model_hasMany() {
 	var user User
 	err := db.Model(&user).
 		Column("user.*").
-		Relation("Profiles", func(q *orm.Query) (*orm.Query, error) {
+		Relation("Profiles", func(q *pg.Query) (*pg.Query, error) {
 			return q.Where("active IS TRUE"), nil
 		}).
 		First()
diff --git a/orm/query.go b/orm/query.go
index 8e35e77f..e8ac4b8a 100644
--- a/orm/query.go
+++ b/orm/query.go
@@ -483,7 +483,7 @@ func (q *Query) WhereOr(condition string, params ...interface{}) *Query {
 // WhereGroup encloses conditions added in the function in parentheses.
 //
 //    q.Where("TRUE").
-//    	WhereGroup(func(q *orm.Query) (*orm.Query, error) {
+//    	WhereGroup(func(q *pg.Query) (*pg.Query, error) {
 //    		q = q.WhereOr("FALSE").WhereOr("TRUE").
 //    		return q, nil
 //    	})
@@ -498,7 +498,7 @@ func (q *Query) WhereGroup(fn func(*Query) (*Query, error)) *Query {
 // WhereGroup encloses conditions added in the function in parentheses.
 //
 //    q.Where("TRUE").
-//    	WhereNotGroup(func(q *orm.Query) (*orm.Query, error) {
+//    	WhereNotGroup(func(q *pg.Query) (*pg.Query, error) {
 //    		q = q.WhereOr("FALSE").WhereOr("TRUE").
 //    		return q, nil
 //    	})
@@ -513,7 +513,7 @@ func (q *Query) WhereNotGroup(fn func(*Query) (*Query, error)) *Query {
 // WhereOrGroup encloses conditions added in the function in parentheses.
 //
 //    q.Where("TRUE").
-//    	WhereOrGroup(func(q *orm.Query) (*orm.Query, error) {
+//    	WhereOrGroup(func(q *pg.Query) (*pg.Query, error) {
 //    		q = q.Where("FALSE").Where("TRUE").
 //    		return q, nil
 //    	})
@@ -528,7 +528,7 @@ func (q *Query) WhereOrGroup(fn func(*Query) (*Query, error)) *Query {
 // WhereOrGroup encloses conditions added in the function in parentheses.
 //
 //    q.Where("TRUE").
-//    	WhereOrGroup(func(q *orm.Query) (*orm.Query, error) {
+//    	WhereOrGroup(func(q *pg.Query) (*pg.Query, error) {
 //    		q = q.Where("FALSE").Where("TRUE").
 //    		return q, nil
 //    	})
diff --git a/pg.go b/pg.go
index 972c7c20..923ef6be 100644
--- a/pg.go
+++ b/pg.go
@@ -17,16 +17,6 @@ var Discard orm.Discard
 // PostgreSQL NULL.
 type NullTime = types.NullTime
 
-// Model returns new query for the optional model.
-func Model(model ...interface{}) *orm.Query {
-	return orm.NewQuery(nil, model...)
-}
-
-// ModelContext returns a new query for the optional model with a context.
-func ModelContext(c context.Context, model ...interface{}) *orm.Query {
-	return orm.NewQueryContext(c, nil, model...)
-}
-
 // Scan returns ColumnScanner that copies the columns in the
 // row into the values.
 func Scan(values ...interface{}) orm.ColumnScanner {
@@ -96,6 +86,46 @@ func SetLogger(logger internal.Logging) {
 
 //------------------------------------------------------------------------------
 
+type Query = orm.Query
+
+// Model returns a new query for the optional model.
+func Model(model ...interface{}) *Query {
+	return orm.NewQuery(nil, model...)
+}
+
+// ModelContext returns a new query for the optional model with a context.
+func ModelContext(c context.Context, model ...interface{}) *Query {
+	return orm.NewQueryContext(c, nil, model...)
+}
+
+// DBI is a DB interface implemented by *DB and *Tx.
+type DBI interface {
+	Model(model ...interface{}) *Query
+	ModelContext(c context.Context, model ...interface{}) *Query
+
+	Exec(query interface{}, params ...interface{}) (Result, error)
+	ExecContext(c context.Context, query interface{}, params ...interface{}) (Result, error)
+	ExecOne(query interface{}, params ...interface{}) (Result, error)
+	ExecOneContext(c context.Context, query interface{}, params ...interface{}) (Result, error)
+	Query(model, query interface{}, params ...interface{}) (Result, error)
+	QueryContext(c context.Context, model, query interface{}, params ...interface{}) (Result, error)
+	QueryOne(model, query interface{}, params ...interface{}) (Result, error)
+	QueryOneContext(c context.Context, model, query interface{}, params ...interface{}) (Result, error)
+
+	Begin() (*Tx, error)
+	RunInTransaction(ctx context.Context, fn func(*Tx) error) error
+
+	CopyFrom(r io.Reader, query interface{}, params ...interface{}) (Result, error)
+	CopyTo(w io.Writer, query interface{}, params ...interface{}) (Result, error)
+}
+
+var (
+	_ DBI = (*DB)(nil)
+	_ DBI = (*Tx)(nil)
+)
+
+//------------------------------------------------------------------------------
+
 // Strings is a type alias for a slice of strings.
 type Strings []string
 
diff --git a/tx.go b/tx.go
index f77f6c05..db444ff6 100644
--- a/tx.go
+++ b/tx.go
@@ -279,12 +279,12 @@ func (tx *Tx) queryOne(
 }
 
 // Model is an alias for DB.Model.
-func (tx *Tx) Model(model ...interface{}) *orm.Query {
+func (tx *Tx) Model(model ...interface{}) *Query {
 	return orm.NewQuery(tx, model...)
 }
 
 // ModelContext acts like Model but additionally receives a context.
-func (tx *Tx) ModelContext(c context.Context, model ...interface{}) *orm.Query {
+func (tx *Tx) ModelContext(c context.Context, model ...interface{}) *Query {
 	return orm.NewQueryContext(c, tx, model...)
 }