class PG::TypeMapByColumn

This type map casts values by a coder assigned per field/column.

Each PG::TypeMapByColumn has a fixed list of either encoders or decoders, that is defined at TypeMapByColumn.new . A type map with encoders is usable for type casting query bind parameters and COPY data for PG::Connection#put_copy_data . A type map with decoders is usable for type casting of result values and COPY data from PG::Connection#get_copy_data .

PG::TypeMapByColumn objects are in particular useful in conjunction with prepared statements, since they can be cached alongside with the statement handle.

This type map strategy is also used internally by PG::TypeMapByOid, when the number of rows of a result set exceeds a given limit.