dialect/sql/sqlgraph: allow setting stmt modifiers for create-one

dialect/sql/sqlgraph/graph.go

@@ -344,7 +344,20 @@ type (
 		ID     *FieldSpec
 		Fields []*FieldSpec
 		Edges  []*EdgeSpec
+
+		// The Modifiers option allows providing custom functions to
+		// modify the INSERT statement of the node before it is executed.
+		//
+		//	sqlgraph.CreateSpec{
+		//		Modifiers: []func(*sql.InsertBuilder) {
+		//			OnConflictOptions(...),
+		//			ReturningOptions(...),
+		//		},
+		//	}
+		//
+		Modifiers []func(*sql.InsertBuilder)
 	}
+
 	// BatchCreateSpec holds the information for creating
 	// multiple nodes in the graph.
 	BatchCreateSpec struct {
@@ -958,6 +971,9 @@ func (c *creator) insert(ctx context.Context, tx dialect.ExecQuerier, insert *sq
 		query, args := insert.Query()
 		return tx.Exec(ctx, query, args, &res)
 	}
+	for _, m := range c.CreateSpec.Modifiers {
+		m(insert)
+	}
 	id, err := insertLastID(ctx, tx, insert.Returning(c.ID.Column))
 	if err != nil {
 		return err

dialect/sql/sqlgraph/graph_test.go

@@ -858,6 +858,29 @@ func TestCreateNode(t *testing.T) {
 				m.ExpectCommit()
 			},
 		},
+		{
+			name: "modifiers",
+			spec: &CreateSpec{
+				Table: "users",
+				ID:    &FieldSpec{Column: "id"},
+				Fields: []*FieldSpec{
+					{Column: "age", Type: field.TypeInt, Value: 30},
+					{Column: "name", Type: field.TypeString, Value: "a8m"},
+				},
+				Modifiers: []func(i *sql.InsertBuilder){
+					func(i *sql.InsertBuilder) {
+						i.OnConflict(sql.ResolveWithNewValues())
+					},
+				},
+			},
+			expect: func(m sqlmock.Sqlmock) {
+				m.ExpectBegin()
+				m.ExpectExec(escape("INSERT INTO `users` (`age`, `name`) VALUES (?, ?) ON DUPLICATE KEY UPDATE `age` = VALUES(`age`), `name` = VALUES(`name`)")).
+					WithArgs(30, "a8m").
+					WillReturnResult(sqlmock.NewResult(1, 1))
+				m.ExpectCommit()
+			},
+		},
 		{
 			name: "fields/user-defined-id",
 			spec: &CreateSpec{
@@ -1148,7 +1171,7 @@ func TestCreateNode(t *testing.T) {
 			db, mock, err := sqlmock.New()
 			require.NoError(t, err)
 			tt.expect(mock)
-			err = CreateNode(context.Background(), sql.OpenDB("", db), tt.spec)
+			err = CreateNode(context.Background(), sql.OpenDB(dialect.MySQL, db), tt.spec)
 			require.Equal(t, tt.wantErr, err != nil, err)
 		})
 	}