gormschema: support view (#45)

README.md

@@ -129,6 +129,66 @@ env "gorm" {
 }
 ```
 
+### Extra Features
+
+#### Views
+
+> Note: Views are available for logged-in users, run `atlas login` if you haven't already. To learn more about logged-in features for Atlas, visit [Feature Availability](https://atlasgo.io/features#database-features).
+
+To define a Go struct as a database `VIEW`, implement the `ViewDef` method as follow:
+```go
+// User is a regular gorm.Model stored in the "users" table.
+type User struct {
+  gorm.Model
+  Name string
+  Age  int
+}
+
+// WorkingAgedUsers is mapped to the VIEW definition below.
+type WorkingAgedUsers struct {
+  Name string
+  Age  int
+}
+
+func (WorkingAgedUsers) ViewDef(dialect string) []gormschema.ViewOption {
+  return []gormschema.ViewOption{
+    gormschema.BuildStmt(func(db *gorm.DB) *gorm.DB {
+      return db.Model(&User{}).Where("age BETWEEN 18 AND 65").Select("name, age")
+    }),
+  }
+}
+```
+In order to pass a plain `CREATE VIEW` statement, use the `CreateStmt` as follows:
+```go
+type BotlTracker struct {
+  ID   uint
+  Name string
+}
+
+func (BotlTracker) ViewDef(dialect string) []gormschema.ViewOption {
+  var stmt string
+  switch dialect {
+  case "mysql":
+    stmt = "CREATE VIEW botl_trackers AS SELECT id, name FROM pets WHERE name LIKE 'botl%'"
+  }
+  return []gormschema.ViewOption{
+    gormschema.CreateStmt(stmt),
+  }
+}
+```
+To include both VIEWs and TABLEs in the migration generation, pass all models to the `Load` function:
+```go
+stmts, err := gormschema.New("mysql").Load(
+  &models.User{},			// Table-based model.
+  &models.WorkingAgedUsers{},	// View-based model.
+)
+```
+The view-based model works just like a regular models in GORM queries. However, make sure the view name is identical to the struct name, and in case they are differ, configure the name using the `TableName` method:
+```go
+func (WorkingAgedUsers) TableName() string {
+  return "working_aged_users_custom_name" // View name is different than pluralized struct name.
+}
+```
 ### Additional Configuration
 
 To supply custom `gorm.Config{}` object to the provider use the [Go Program Mode](#as-go-file) with
@@ -210,9 +270,9 @@ The provider supports the following databases:
   you should use the following code:
   ```go
   stmts, err := gormschema.New("mysql",
-  	gormschema.WithJoinTable(
-  		&Models.Person{}, "Addresses", &Models.PersonAddress{},
-  	),
+    gormschema.WithJoinTable(
+      &Models.Person{}, "Addresses", &Models.PersonAddress{},
+    ),
   ).Load(&Models.Address{}, &Models.Person{})
   ```
 

go.mod

@@ -8,7 +8,7 @@ require (
 	ariga.io/atlas-go-sdk v0.2.3
 	github.com/alecthomas/kong v0.7.1
 	github.com/stretchr/testify v1.8.4
-	golang.org/x/tools v0.17.0
+	golang.org/x/tools v0.18.0
 	gorm.io/driver/mysql v1.5.1
 	gorm.io/driver/postgres v1.5.2
 	gorm.io/driver/sqlite v1.5.2

go.sum

@@ -118,8 +118,8 @@ golang.org/x/net v0.7.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
 golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
 golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
 golang.org/x/net v0.14.0/go.mod h1:PpSgVXXLK0OxS0F31C1/tv6XNguvCrnXIDrFMspZIUI=
-golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
-golang.org/x/net v0.20.0/go.mod h1:z8BVo6PvndSri0LbOE3hAn0apkU+1YvI6E70E9jsnvY=
+golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
+golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -136,8 +136,9 @@ golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=
 golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.17.0 h1:25cE3gD+tdBA7lp7QfhuV+rJiE9YXTcS3VG1SqssI/Y=
+golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
@@ -157,8 +158,8 @@ golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGm
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
-golang.org/x/tools v0.17.0 h1:FvmRgNOcs3kOa+T20R1uhfP9F6HgG2mfxDv1vrx1Htc=
-golang.org/x/tools v0.17.0/go.mod h1:xsh6VxdV005rRVaS6SSAf9oiAqljS7UZUacMZ8Bnsps=
+golang.org/x/tools v0.18.0 h1:k8NLag8AGHnn+PHbl7g43CtqZAwG60vZkLqgyZgIHgQ=
+golang.org/x/tools v0.18.0/go.mod h1:GL7B4CwcLLeo59yx/9UWWuNOW1n3VZ4f5axWfML7Lcg=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=

gormschema/gorm.go

@@ -5,6 +5,7 @@ import (
 	"database/sql/driver"
 	"errors"
 	"fmt"
+	"reflect"
 	"slices"
 
 	"ariga.io/atlas-go-sdk/recordriver"
@@ -45,6 +46,18 @@ func WithConfig(cfg *gorm.Config) Option {
 
 // Load loads the models and returns the DDL statements representing the schema.
 func (l *Loader) Load(models ...any) (string, error) {
+	var (
+		views  []ViewDefiner
+		tables []any
+	)
+	for _, obj := range models {
+		switch view := obj.(type) {
+		case ViewDefiner:
+			views = append(views, view)
+		default:
+			tables = append(tables, obj)
+		}
+	}
 	var di gorm.Dialector
 	switch l.dialect {
 	case "sqlite":
@@ -91,21 +104,22 @@ func (l *Loader) Load(models ...any) (string, error) {
 			return "", err
 		}
 	}
-	if err = db.AutoMigrate(models...); err != nil {
+	if err = db.AutoMigrate(tables...); err != nil {
+		return "", err
+	}
+	db, err = gorm.Open(dialector{Dialector: di}, l.config)
+	if err != nil {
+		return "", err
+	}
+	cm, ok := db.Migrator().(*migrator)
+	if !ok {
+		return "", fmt.Errorf("unexpected migrator type: %T", db.Migrator())
+	}
+	if err = cm.CreateViews(views); err != nil {
 		return "", err
 	}
 	if !l.config.DisableForeignKeyConstraintWhenMigrating && l.dialect != "sqlite" {
-		db, err = gorm.Open(dialector{
-			Dialector: di,
-		}, l.config)
-		if err != nil {
-			return "", err
-		}
-		cm, ok := db.Migrator().(*migrator)
-		if !ok {
-			return "", err
-		}
-		if err = cm.CreateConstraints(models); err != nil {
+		if err = cm.CreateConstraints(tables); err != nil {
 			return "", err
 		}
 	}
@@ -125,8 +139,8 @@ type dialector struct {
 	gorm.Dialector
 }
 
-// Migrator returns a new gorm.Migrator which can be used to automatically create all Constraints
-// on existing tables.
+// Migrator returns a new gorm.Migrator, which can be used to extend the default migrator,
+// helping to create constraints and views ...
 func (d dialector) Migrator(db *gorm.DB) gorm.Migrator {
 	return &migrator{
 		Migrator: gormig.Migrator{
@@ -179,6 +193,29 @@ func (m *migrator) CreateConstraints(models []any) error {
 	return nil
 }
 
+// CreateViews creates the given "view-based" models
+func (m *migrator) CreateViews(views []ViewDefiner) error {
+	for _, view := range views {
+		viewName := m.DB.Config.NamingStrategy.TableName(indirect(reflect.TypeOf(view)).Name())
+		if namer, ok := view.(interface {
+			TableName() string
+		}); ok {
+			viewName = namer.TableName()
+		}
+		viewBuilder := &viewBuilder{
+			db:       m.DB,
+			viewName: viewName,
+		}
+		for _, opt := range view.ViewDef(m.Dialector.Name()) {
+			opt(viewBuilder)
+		}
+		if err := m.DB.Exec(viewBuilder.createStmt).Error; err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // WithJoinTable sets up a join table for the given model and field.
 func WithJoinTable(model any, field string, jointable any) Option {
 	return func(l *Loader) {
@@ -187,3 +224,48 @@ func WithJoinTable(model any, field string, jointable any) Option {
 		})
 	}
 }
+
+func indirect(t reflect.Type) reflect.Type {
+	for t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	return t
+}
+
+type (
+	// ViewOption configures a viewBuilder.
+	ViewOption func(*viewBuilder)
+	// ViewDefiner defines a view.
+	ViewDefiner interface {
+		ViewDef(dialect string) []ViewOption
+	}
+	viewBuilder struct {
+		db         *gorm.DB
+		createStmt string
+		// viewName is only used for the BuildStmt option.
+		// BuildStmt returns only a subquery; viewName helps to create a full CREATE VIEW statement.
+		viewName string
+	}
+)
+
+// CreateStmt accepts raw SQL to create a CREATE VIEW statement.
+func CreateStmt(stmt string) ViewOption {
+	return func(b *viewBuilder) {
+		b.createStmt = b.db.ToSQL(func(tx *gorm.DB) *gorm.DB {
+			return tx.Exec(stmt)
+		})
+	}
+}
+
+// BuildStmt accepts a function with gorm query builder to create a CREATE VIEW statement.
+// With this option, the view's name will be the same as the model's table name
+func BuildStmt(fn func(db *gorm.DB) *gorm.DB) ViewOption {
+	return func(b *viewBuilder) {
+		vd := b.db.ToSQL(func(tx *gorm.DB) *gorm.DB {
+			return fn(tx).
+				Unscoped(). // Skip gorm deleted_at filtering.
+				Find(nil)   // Execute the query and convert it to SQL.
+		})
+		b.createStmt = fmt.Sprintf("CREATE VIEW %s AS %s", b.viewName, vd)
+	}
+}

gormschema/gorm_test.go

@@ -1,10 +1,11 @@
-package gormschema
+package gormschema_test
 
 import (
 	"os"
 	"testing"
 
 	"ariga.io/atlas-go-sdk/recordriver"
+	"ariga.io/atlas-provider-gorm/gormschema"
 	ckmodels "ariga.io/atlas-provider-gorm/internal/testdata/circularfks"
 	"ariga.io/atlas-provider-gorm/internal/testdata/customjointable"
 	"ariga.io/atlas-provider-gorm/internal/testdata/models"
@@ -14,12 +15,12 @@ import (
 
 func TestSQLiteConfig(t *testing.T) {
 	resetSession()
-	l := New("sqlite")
-	sql, err := l.Load(models.Pet{}, models.User{}, ckmodels.Event{}, ckmodels.Location{})
+	l := gormschema.New("sqlite")
+	sql, err := l.Load(models.WorkingAgedUsers{}, models.Pet{}, models.User{}, ckmodels.Event{}, ckmodels.Location{}, models.TopPetOwner{})
 	require.NoError(t, err)
 	requireEqualContent(t, sql, "testdata/sqlite_default")
 	resetSession()
-	l = New("sqlite", WithConfig(&gorm.Config{
+	l = gormschema.New("sqlite", gormschema.WithConfig(&gorm.Config{
 		DisableForeignKeyConstraintWhenMigrating: true,
 	}))
 	sql, err = l.Load(models.Pet{}, models.User{})
@@ -30,12 +31,12 @@ func TestSQLiteConfig(t *testing.T) {
 
 func TestPostgreSQLConfig(t *testing.T) {
 	resetSession()
-	l := New("postgres")
-	sql, err := l.Load(ckmodels.Location{}, ckmodels.Event{}, models.User{}, models.Pet{})
+	l := gormschema.New("postgres")
+	sql, err := l.Load(models.WorkingAgedUsers{}, ckmodels.Location{}, ckmodels.Event{}, models.User{}, models.Pet{}, models.TopPetOwner{})
 	require.NoError(t, err)
 	requireEqualContent(t, sql, "testdata/postgresql_default")
 	resetSession()
-	l = New("postgres", WithConfig(
+	l = gormschema.New("postgres", gormschema.WithConfig(
 		&gorm.Config{
 			DisableForeignKeyConstraintWhenMigrating: true,
 		}))
@@ -46,12 +47,12 @@ func TestPostgreSQLConfig(t *testing.T) {
 
 func TestMySQLConfig(t *testing.T) {
 	resetSession()
-	l := New("mysql")
-	sql, err := l.Load(ckmodels.Location{}, ckmodels.Event{}, models.User{}, models.Pet{})
+	l := gormschema.New("mysql")
+	sql, err := l.Load(models.WorkingAgedUsers{}, ckmodels.Location{}, ckmodels.Event{}, models.User{}, models.Pet{}, models.TopPetOwner{})
 	require.NoError(t, err)
 	requireEqualContent(t, sql, "testdata/mysql_default")
 	resetSession()
-	l = New("mysql", WithConfig(
+	l = gormschema.New("mysql", gormschema.WithConfig(
 		&gorm.Config{
 			DisableForeignKeyConstraintWhenMigrating: true,
 		},
@@ -60,20 +61,20 @@ func TestMySQLConfig(t *testing.T) {
 	require.NoError(t, err)
 	requireEqualContent(t, sql, "testdata/mysql_no_fk")
 	resetSession()
-	l = New("mysql", WithJoinTable(&customjointable.Person{}, "Addresses", &customjointable.PersonAddress{}))
-	sql, err = l.Load(customjointable.Address{}, customjointable.Person{})
+	l = gormschema.New("mysql", gormschema.WithJoinTable(&customjointable.Person{}, "Addresses", &customjointable.PersonAddress{}))
+	sql, err = l.Load(customjointable.Address{}, customjointable.Person{}, customjointable.TopCrowdedAddresses{})
 	require.NoError(t, err)
 	requireEqualContent(t, sql, "testdata/mysql_custom_join_table")
 }
 
 func TestSQLServerConfig(t *testing.T) {
 	resetSession()
-	l := New("sqlserver")
-	sql, err := l.Load(ckmodels.Location{}, ckmodels.Event{}, models.User{}, models.Pet{})
+	l := gormschema.New("sqlserver")
+	sql, err := l.Load(models.WorkingAgedUsers{}, ckmodels.Location{}, ckmodels.Event{}, models.User{}, models.Pet{}, models.TopPetOwner{})
 	require.NoError(t, err)
 	requireEqualContent(t, sql, "testdata/sqlserver_default")
 	resetSession()
-	l = New("sqlserver", WithConfig(
+	l = gormschema.New("sqlserver", gormschema.WithConfig(
 		&gorm.Config{
 			DisableForeignKeyConstraintWhenMigrating: true,
 		}))

gormschema/testdata/mysql_custom_join_table

@@ -1,5 +1,6 @@
 CREATE TABLE `addresses` (`id` bigint AUTO_INCREMENT,`name` longtext,PRIMARY KEY (`id`));
 CREATE TABLE `people` (`id` bigint AUTO_INCREMENT,`name` longtext,PRIMARY KEY (`id`));
 CREATE TABLE `person_addresses` (`person_id` bigint,`address_id` bigint,`created_at` datetime(3) NULL,`deleted_at` datetime(3) NULL,PRIMARY KEY (`person_id`,`address_id`));
+CREATE VIEW top_crowded_addresses AS SELECT address_id, COUNT(person_id) AS count FROM person_addresses GROUP BY address_id ORDER BY count DESC LIMIT 10;
 ALTER TABLE `person_addresses` ADD CONSTRAINT `fk_person_addresses_address` FOREIGN KEY (`address_id`) REFERENCES `addresses`(`id`);
 ALTER TABLE `person_addresses` ADD CONSTRAINT `fk_person_addresses_person` FOREIGN KEY (`person_id`) REFERENCES `people`(`id`);

gormschema/testdata/mysql_default

@@ -1,7 +1,9 @@
 CREATE TABLE `events` (`eventId` varchar(191),`locationId` varchar(191),PRIMARY KEY (`eventId`),UNIQUE INDEX `idx_events_location_id` (`locationId`));
 CREATE TABLE `locations` (`locationId` varchar(191),`eventId` varchar(191),PRIMARY KEY (`locationId`),UNIQUE INDEX `idx_locations_event_id` (`eventId`));
-CREATE TABLE `users` (`id` bigint unsigned AUTO_INCREMENT,`created_at` datetime(3) NULL,`updated_at` datetime(3) NULL,`deleted_at` datetime(3) NULL,`name` longtext,PRIMARY KEY (`id`),INDEX `idx_users_deleted_at` (`deleted_at`));
+CREATE TABLE `users` (`id` bigint unsigned AUTO_INCREMENT,`created_at` datetime(3) NULL,`updated_at` datetime(3) NULL,`deleted_at` datetime(3) NULL,`name` longtext,`age` bigint,PRIMARY KEY (`id`),INDEX `idx_users_deleted_at` (`deleted_at`));
 CREATE TABLE `pets` (`id` bigint unsigned AUTO_INCREMENT,`created_at` datetime(3) NULL,`updated_at` datetime(3) NULL,`deleted_at` datetime(3) NULL,`name` longtext,`user_id` bigint unsigned,PRIMARY KEY (`id`),INDEX `idx_pets_deleted_at` (`deleted_at`));
+CREATE VIEW working_aged_users AS SELECT name, age FROM `users` WHERE age BETWEEN 18 AND 65;
+CREATE VIEW top_pet_owners AS SELECT user_id, COUNT(id) AS pet_count FROM pets GROUP BY user_id ORDER BY pet_count DESC LIMIT 10;
 ALTER TABLE `events` ADD CONSTRAINT `fk_locations_event` FOREIGN KEY (`locationId`) REFERENCES `locations`(`locationId`);
 ALTER TABLE `locations` ADD CONSTRAINT `fk_events_location` FOREIGN KEY (`eventId`) REFERENCES `events`(`eventId`);
 ALTER TABLE `pets` ADD CONSTRAINT `fk_users_pets` FOREIGN KEY (`user_id`) REFERENCES `users`(`id`);

gormschema/testdata/postgresql_default

@@ -2,10 +2,12 @@ CREATE TABLE "events" ("eventId" varchar(191),"locationId" varchar(191),PRIMARY
 CREATE UNIQUE INDEX IF NOT EXISTS "idx_events_location_id" ON "events" ("locationId");
 CREATE TABLE "locations" ("locationId" varchar(191),"eventId" varchar(191),PRIMARY KEY ("locationId"));
 CREATE UNIQUE INDEX IF NOT EXISTS "idx_locations_event_id" ON "locations" ("eventId");
-CREATE TABLE "users" ("id" bigserial,"created_at" timestamptz,"updated_at" timestamptz,"deleted_at" timestamptz,"name" text,PRIMARY KEY ("id"));
+CREATE TABLE "users" ("id" bigserial,"created_at" timestamptz,"updated_at" timestamptz,"deleted_at" timestamptz,"name" text,"age" bigint,PRIMARY KEY ("id"));
 CREATE INDEX IF NOT EXISTS "idx_users_deleted_at" ON "users" ("deleted_at");
 CREATE TABLE "pets" ("id" bigserial,"created_at" timestamptz,"updated_at" timestamptz,"deleted_at" timestamptz,"name" text,"user_id" bigint,PRIMARY KEY ("id"));
 CREATE INDEX IF NOT EXISTS "idx_pets_deleted_at" ON "pets" ("deleted_at");
+CREATE VIEW working_aged_users AS SELECT name, age FROM "users" WHERE age BETWEEN 18 AND 65;
+CREATE VIEW top_pet_owners AS SELECT user_id, COUNT(id) AS pet_count FROM pets GROUP BY user_id ORDER BY pet_count DESC LIMIT 10;
 ALTER TABLE "events" ADD CONSTRAINT "fk_locations_event" FOREIGN KEY ("locationId") REFERENCES "locations"("locationId");
 ALTER TABLE "locations" ADD CONSTRAINT "fk_events_location" FOREIGN KEY ("eventId") REFERENCES "events"("eventId");
 ALTER TABLE "pets" ADD CONSTRAINT "fk_users_pets" FOREIGN KEY ("user_id") REFERENCES "users"("id");