ent · a8m · Jan 23, 2022 · Jul 9, 2021
diff --git a/.golangci.yml b/.golangci.yml
@@ -67,4 +67,4 @@ issues:
         - staticcheck
     - path: entc/gen/graph.go
       linters:
-        - gocritic
+        - gocritic
diff --git a/dialect/sql/schema/schema.go b/dialect/sql/schema/schema.go
@@ -409,9 +409,6 @@ const (
 
 // ConstName returns the constant name of a reference option. It's used by entc for printing the constant name in templates.
 func (r ReferenceOption) ConstName() string {
-	if r == NoAction {
-		return ""
-	}
 	return strings.ReplaceAll(strings.Title(strings.ToLower(string(r))), " ", "")
 }
 

diff --git a/doc/md/schema-edges.md b/doc/md/schema-edges.md
@@ -1034,6 +1034,12 @@ func (Card) Edges() []ent.Edge {
 
 If the example above, a card entity cannot be created without its owner. 
 
+:::info
+Note that, starting with [v0.10](https://github.com/ent/ent/releases/tag/v0.10.0), foreign key columns are created
+as `NOT NULL` in the database for required edges that are not [self-reference](#o2m-same-type). In order to migrate
+existing foreign key columns, use the [Atlas Migration](migrate.md#atlas-integration) option.
+:::
+
 ## StorageKey
 
 By default, Ent configures edge storage-keys by the edge-owner (the schema that holds the `edge.To`), and not the by

diff --git a/entc/gen/graph.go b/entc/gen/graph.go
@@ -456,15 +456,20 @@ func (g *Graph) Tables() (all []*schema.Table, err error) {
 			}
 			switch e.Rel.Type {
 			case O2O, O2M:
-				// The "owner" is the table that owns the relation (we set the foreign-key on)
-				// and "ref" is the referenced table.
+				// The "owner" is the table that owns the relation (we set
+				// the foreign-key on) and "ref" is the referenced table.
 				owner, ref := tables[e.Rel.Table], tables[n.Table()]
 				pk := ref.PrimaryKey[0]
 				column := &schema.Column{Name: e.Rel.Column(), Size: pk.Size, Type: pk.Type, Unique: e.Rel.Type == O2O, SchemaType: pk.SchemaType, Nullable: true}
+				// If it's not a circular reference (self-referencing table),
+				// and the inverse edge is required, make it non-nullable.
+				if n != e.Type && e.Ref != nil && !e.Ref.Optional {
+					column.Nullable = false
+				}
 				mayAddColumn(owner, column)
 				owner.AddForeignKey(&schema.ForeignKey{
 					RefTable:   ref,
-					OnDelete:   deleteAction(e),
+					OnDelete:   deleteAction(e, column),
 					Columns:    []*schema.Column{column},
 					RefColumns: []*schema.Column{ref.PrimaryKey[0]},
 					Symbol:     fkSymbol(e, owner, ref),
@@ -473,10 +478,15 @@ func (g *Graph) Tables() (all []*schema.Table, err error) {
 				ref, owner := tables[e.Type.Table()], tables[e.Rel.Table]
 				pk := ref.PrimaryKey[0]
 				column := &schema.Column{Name: e.Rel.Column(), Size: pk.Size, Type: pk.Type, SchemaType: pk.SchemaType, Nullable: true}
+				// If it's not a circular reference (self-referencing table),
+				// and the edge is non-optional (required), make it non-nullable.
+				if n != e.Type && !e.Optional {
+					column.Nullable = false
+				}
 				mayAddColumn(owner, column)
 				owner.AddForeignKey(&schema.ForeignKey{
 					RefTable:   ref,
-					OnDelete:   deleteAction(e),
+					OnDelete:   deleteAction(e, column),
 					Columns:    []*schema.Column{column},
 					RefColumns: []*schema.Column{ref.PrimaryKey[0]},
 					Symbol:     fkSymbol(e, owner, ref),
@@ -563,8 +573,11 @@ func fkSymbols(e *Edge, c1, c2 *schema.Column) (string, string) {
 }
 
 // deleteAction returns the referential action for DELETE operations of the given edge.
-func deleteAction(e *Edge) schema.ReferenceOption {
-	action := schema.SetNull
+func deleteAction(e *Edge, c *schema.Column) schema.ReferenceOption {
+	action := schema.NoAction
+	if c.Nullable {
+		action = schema.SetNull
+	}
 	if ant := e.EntSQL(); ant != nil && ant.OnDelete != "" {
 		action = schema.ReferenceOption(ant.OnDelete)
 	}

diff --git a/entc/integration/cascadelete/ent/migrate/schema.go b/entc/integration/cascadelete/ent/migrate/schema.go
diff --git a/entc/integration/edgefield/ent/migrate/schema.go b/entc/integration/edgefield/ent/migrate/schema.go
diff --git a/entc/integration/ent/migrate/schema.go b/entc/integration/ent/migrate/schema.go
diff --git a/entc/integration/migrate/entv2/car_create.go b/entc/integration/migrate/entv2/car_create.go
diff --git a/entc/integration/migrate/entv2/car_update.go b/entc/integration/migrate/entv2/car_update.go
diff --git a/entc/integration/migrate/entv2/migrate/schema.go b/entc/integration/migrate/entv2/migrate/schema.go
diff --git a/entc/integration/migrate/entv2/schema/user.go b/entc/integration/migrate/entv2/schema/user.go
@@ -120,7 +120,7 @@ func (User) Indexes() []ent.Index {
 		// this index on MySQL.
 		index.Fields("description").
 			Annotations(entsql.Prefix(100)),
-		// deleting old indexes (name, address),
+		// Deleting old indexes (name, address),
 		// and defining a new one.
 		index.Fields("phone", "age").
 			Unique(),
@@ -135,7 +135,10 @@ func (Car) Edges() []ent.Edge {
 	return []ent.Edge{
 		edge.From("owner", User.Type).
 			Ref("car").
-			Unique(),
+			Unique().
+			// Make a M20 edge from nullable to required.
+			// Requires column and foreign-key migration.
+			Required(),
 	}
 }
 

diff --git a/entc/integration/migrate/migrate_test.go b/entc/integration/migrate/migrate_test.go
@@ -128,13 +128,14 @@ func TestSQLite(t *testing.T) {
 	)
 
 	SanityV2(t, drv.Dialect(), client)
-	idRange(t, client.Car.Create().SaveX(ctx).ID, 0, 1<<32)
+	u := client.User.Create().SetAge(1).SetName("x").SetNickname("x'").SetPhone("y").SaveX(ctx)
+	idRange(t, client.Car.Create().SetOwner(u).SaveX(ctx).ID, 0, 1<<32)
 	idRange(t, client.Conversion.Create().SaveX(ctx).ID, 1<<32-1, 2<<32)
 	idRange(t, client.CustomType.Create().SaveX(ctx).ID, 2<<32-1, 3<<32)
 	idRange(t, client.Group.Create().SaveX(ctx).ID, 3<<32-1, 4<<32)
 	idRange(t, client.Media.Create().SaveX(ctx).ID, 4<<32-1, 5<<32)
 	idRange(t, client.Pet.Create().SaveX(ctx).ID, 5<<32-1, 6<<32)
-	idRange(t, client.User.Create().SetAge(1).SetName("x").SetNickname("x'").SetPhone("y").SaveX(ctx).ID, 6<<32-1, 7<<32)
+	idRange(t, u.ID, 6<<32-1, 7<<32)
 
 	// Override the default behavior of LIKE in SQLite.
 	// https://www.sqlite.org/pragma.html#pragma_case_sensitive_like
@@ -163,11 +164,12 @@ func V1ToV2(t *testing.T, dialect string, clientv1 *entv1.Client, clientv2 *entv
 	require.NoError(t, clientv2.Schema.Create(ctx, migratev2.WithGlobalUniqueID(true), schema.WithAtlas(true)), "should not create additional resources on multiple runs")
 	SanityV2(t, dialect, clientv2)
 
-	idRange(t, clientv2.Car.Create().SaveX(ctx).ID, 0, 1<<32)
+	u := clientv2.User.Create().SetAge(1).SetName("foo").SetNickname("nick_foo").SetPhone("phone").SaveX(ctx)
+	idRange(t, clientv2.Car.Create().SetOwner(u).SaveX(ctx).ID, 0, 1<<32)
 	idRange(t, clientv2.Conversion.Create().SaveX(ctx).ID, 1<<32-1, 2<<32)
 	// Since "users" created in the migration of v1, it will occupy the range of 1<<32-1 ... 2<<32-1,
 	// even though they are ordered differently in the migration of v2 (groups, pets, users).
-	idRange(t, clientv2.User.Create().SetAge(1).SetName("foo").SetNickname("nick_foo").SetPhone("phone").SaveX(ctx).ID, 3<<32-1, 4<<32)
+	idRange(t, u.ID, 3<<32-1, 4<<32)
 	idRange(t, clientv2.Group.Create().SaveX(ctx).ID, 4<<32-1, 5<<32)
 	idRange(t, clientv2.Media.Create().SaveX(ctx).ID, 5<<32-1, 6<<32)
 	idRange(t, clientv2.Pet.Create().SaveX(ctx).ID, 6<<32-1, 7<<32)

diff --git a/examples/o2o2types/ent/migrate/schema.go b/examples/o2o2types/ent/migrate/schema.go
diff --git a/examples/privacytenant/ent/migrate/schema.go b/examples/privacytenant/ent/migrate/schema.go