original_string: public function get_keys(string $table): ?array
    {
      if ( $tmp = $this->_get_cache($table) ){
        return [
          'keys' => $tmp['keys'],
          'cols' => $tmp['cols']
        ];
      }
      return null;
    }
code: public function get_keys(string $table): ?array
    {
      if ( $tmp = $this->_get_cache($table) ){
        return [
          'keys' => $tmp['keys'],
          'cols' => $tmp['cols']
        ];
      }
      return null;
    }
code_tokens: public function get_keys ( string $ table ) : ? array { if ( $ tmp = $ this -> _get_cache ( $ table ) ) { return [ 'keys' => $ tmp [ 'keys' ] , 'cols' => $ tmp [ 'cols' ] ] ; } return null ; }
docstring: Return the table's keys as an array indexed with the fields names.
  
  ```php
  \bbn\x::dump($db->get_keys("table_users"));
  /*
  (array)[
  "keys" => [
  "PRIMARY" => [
  "columns" => [
  "id",
  ],
  "ref_db" => null,
  "ref_table" => null,
  "ref_column" => null,
  "unique" => 1,
  ],
  "number" => [
  "columns" => [
  "number",
  ],
  "ref_db" => null,
  "ref_table" => null,
  "ref_column" => null,
  "unique" => 1,
  ],
  ],
  "cols" => [
  "id" => [
  "PRIMARY",
  ],
  "number" => [
  "number",
  ],
  ],
  ]
  ```
  
  @param string $table The table's name
  @return null|array
docstring_tokens: Return the table s keys as an array indexed with the fields names .