laravel/framework · error · RuntimeException

This database driver does not support retrieving foreign key

Error message

This database driver does not support retrieving foreign keys.

What it means

Base Grammar::compileForeignKeys() throws RuntimeException when the driver's grammar does not override it. It backs Schema::getForeignKeys(); first-class drivers implement it, so this is hit only with a custom/incomplete grammar.

Source

Thrown at src/Illuminate/Database/Schema/Grammars/Grammar.php:182

     * @throws \RuntimeException
     */
    public function compileVectorIndex(Blueprint $blueprint, Fluent $command)
    {
        throw new RuntimeException('The database driver in use does not support vector indexes.');
    }

    /**
     * Compile the query to determine the foreign keys.
     *
     * @param  string|null  $schema
     * @param  string  $table
     * @return string
     *
     * @throws \RuntimeException
     */
    public function compileForeignKeys($schema, $table)
    {
        throw new RuntimeException('This database driver does not support retrieving foreign keys.');
    }

    /**
     * Compile a rename column command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint  $blueprint
     * @param  \Illuminate\Support\Fluent  $command
     * @return list<string>|string
     */
    public function compileRenameColumn(Blueprint $blueprint, Fluent $command)
    {
        return sprintf('alter table %s rename column %s to %s',
            $this->wrapTable($blueprint),
            $this->wrap($command->from),
            $this->wrap($command->to)
        );
    }

View on GitHub (pinned to bd6b5437e6)

Solutions

  1. Switch to a first-class driver (mysql, pgsql, sqlite, sqlsrv).
  2. Implement compileForeignKeys($schema, $table) on the custom grammar.
  3. Verify the connection binding in config/database.php.

Example fix

// before
$fks = Schema::connection('custom')->getForeignKeys('users');

// after
public function compileForeignKeys($schema, $table)
{
    return 'select ... from information_schema.referential_constraints ...';
}
Defensive patterns

Strategy: type-guard

Validate before calling

$grammar = Schema::getConnection()->getSchemaGrammar();
if ((new \ReflectionMethod($grammar, 'compileForeignKeys'))->getDeclaringClass()->getName()
    === \Illuminate\Database\Schema\Grammars\Grammar::class) {
    throw new \RuntimeException('Foreign key listing unsupported on '.DB::connection()->getDriverName());
}
return Schema::getForeignKeys($table);

Type guard

function driverSupportsForeignKeyListing(): bool
{
    $g = Schema::getConnection()->getSchemaGrammar();

    return (new \ReflectionMethod($g, 'compileForeignKeys'))
        ->getDeclaringClass()->getName() !== \Illuminate\Database\Schema\Grammars\Grammar::class;
}

Try / catch

try {
    $fks = Schema::getForeignKeys($table);
} catch (\RuntimeException $e) {
    $fks = [];
}

Prevention

When it happens

Trigger: Calling Schema::getForeignKeys($table) on a connection whose grammar lacks the override.

Common situations: Custom driver not implementing compileForeignKeys; outdated community driver; wrong connection key resolved to a stub.

Related errors

AI-assisted analysis of laravel/framework@bd6b5437e6 (2026-08-06). Data as JSON: /data/errors/3633cb68e9e4ba63.json. Report an issue: GitHub.