yiisoft/yii2 · error · NotSupportedException

PostgreSQL does not support default value constraints.

Error message

PostgreSQL does not support default value constraints.

What it means

yii\db\pgsql\Schema::loadTableDefaultValues() implements the base Schema's named-DEFAULT-constraint contract, but PostgreSQL, like MySQL, expresses defaults in column DDL rather than as separate constraint objects. The method therefore unconditionally throws NotSupportedException.

Source

Thrown at framework/db/pgsql/Schema.php:287

    {
        return $this->loadTableConstraints($tableName, 'uniques');
    }

    /**
     * {@inheritdoc}
     */
    protected function loadTableChecks($tableName)
    {
        return $this->loadTableConstraints($tableName, 'checks');
    }

    /**
     * {@inheritdoc}
     * @throws NotSupportedException if this method is called.
     */
    protected function loadTableDefaultValues($tableName)
    {
        throw new NotSupportedException('PostgreSQL does not support default value constraints.');
    }

    /**
     * Creates a query builder for the PostgreSQL database.
     * @return QueryBuilder query builder instance
     */
    public function createQueryBuilder()
    {
        return Yii::createObject(QueryBuilder::className(), [$this->db]);
    }

    /**
     * Resolves the table name and schema name (if any).
     * @param TableSchema $table the table metadata object
     * @param string $name the table name
     */
    protected function resolveTableNames($table, $name)
    {

View on GitHub (pinned to 66f00d18a2)

Solutions

Do not call getTableDefaultValues() on PostgreSQL.
Read per-column defaults from getTableSchema($t)->columns[$name]->defaultValue.
Branch on driver name or catch NotSupportedException in generic introspection loops.

Example fix

// before
$defaults = $db->getTableDefaultValues('invoice');

// after
$defaults = array_map(
    fn($c) => $c->defaultValue,
    $db->getTableSchema('invoice', true)->columns
);

Defensive patterns

Strategy: try-catch

Validate before calling

if ($db->driverName === 'pgsql') {
    $defaults = array_map(fn($c) => $c->defaultValue, $db->getTableSchema($t, true)->columns);
} else {
    $defaults = $db->getTableDefaultValues($t);
}

Try / catch

try {
    $defaults = $db->getTableDefaultValues($table);
} catch (\yii\db\NotSupportedException $e) {
    $defaults = []; // pgsql has no named default constraints
}

Prevention

Use column-schema defaults for PostgreSQL.
Maintain a per-driver capability table in schema tooling.
Treat NotSupportedException from getTable* accessors as an empty result, not an error.

When it happens

Trigger: Calling $db->getTableDefaultValues('tbl') on a PostgreSQL connection, usually from generic code that enumerates all constraint accessors without driver awareness.

Common situations: Schema tooling or admin generators written against mssql (the driver that does support named defaults) reused on PostgreSQL; migration diff engines probing every constraint type.

Related errors

AI-assisted analysis of yiisoft/yii2@66f00d18a2 (2026-08-17). Data as JSON: /api/errors/61731b72de1a24dc. Report an issue: GitHub.