public function getTableSchema(): ?TableSchema
    {
        if ($this->_tableSchema === null) {
            $this->_tableSchema = $this->db->getTableSchema($this->tableName);
        }

        return $this->_tableSchema;
    }
public function getTableSchema(): ?TableSchema
    {
        if ($this->_tableSchema === null) {
            $this->_tableSchema = $this->db->getTableSchema($this->tableName);
        }

        return $this->_tableSchema;
    }
public function getTableSchema ( ) : ? TableSchema { if ( $ this -> _tableSchema === null ) { $ this -> _tableSchema = $ this -> db -> getTableSchema ( $ this -> tableName ) ; } return $ this -> _tableSchema ; }
Returns table schema.
@return TableSchema|null
Returns table schema .