system/Database/Postgre/Connection.php
public function _foreignKeyData(string $table): array
	{
		$sql = 'SELECT
                            tc.constraint_name, tc.table_name, kcu.column_name,
                            ccu.table_name AS foreign_table_name,
                            ccu.column_name AS foreign_column_name
                        FROM information_schema.table_constraints AS tc
                        JOIN information_schema.key_column_usage AS kcu
                            ON tc.constraint_name = kcu.constraint_name
                        JOIN information_schema.constraint_column_usage AS ccu
                            ON ccu.constraint_name = tc.constraint_name
                        WHERE constraint_type = ' . $this->escape('FOREIGN KEY') . ' AND
                            tc.table_name = ' . $this->escape($table);

		if (($query = $this->query($sql)) === false)
		{
			throw new DatabaseException(lang('Database.failGetForeignKeyData'));
		}
		$query = $query->getResultObject();

		$retVal = [];
		foreach ($query as $row)
		{
			$obj                     = new \stdClass();
			$obj->constraint_name    = $row->constraint_name;
			$obj->table_name         = $row->table_name;
			$obj->foreign_table_name = $row->foreign_table_name;
			$retVal[]                = $obj;
		}

		return $retVal;
	}
public function _foreignKeyData(string $table): array
	{
		$sql = 'SELECT
                            tc.constraint_name, tc.table_name, kcu.column_name,
                            ccu.table_name AS foreign_table_name,
                            ccu.column_name AS foreign_column_name
                        FROM information_schema.table_constraints AS tc
                        JOIN information_schema.key_column_usage AS kcu
                            ON tc.constraint_name = kcu.constraint_name
                        JOIN information_schema.constraint_column_usage AS ccu
                            ON ccu.constraint_name = tc.constraint_name
                        WHERE constraint_type = ' . $this->escape('FOREIGN KEY') . ' AND
                            tc.table_name = ' . $this->escape($table);

		if (($query = $this->query($sql)) === false)
		{
			throw new DatabaseException(lang('Database.failGetForeignKeyData'));
		}
		$query = $query->getResultObject();

		$retVal = [];
		foreach ($query as $row)
		{
			$obj                     = new \stdClass();
			$obj->constraint_name    = $row->constraint_name;
			$obj->table_name         = $row->table_name;
			$obj->foreign_table_name = $row->foreign_table_name;
			$retVal[]                = $obj;
		}

		return $retVal;
	}
Returns an array of objects with Foreign key data

@param  string $table
@return \stdClass[]
@throws DatabaseException