This type map casts values based on the type OID of the given column in the result set.
Fields with no match to any of the registered type OID / format combination are forwarded to the
Array of all assigned
Threshold for doing Hash lookups versus creation of a dedicated
PG::TypeMapByColumn. The type map will do Hash lookups for each result value, if the number of rows is below or equal
PG::Coder object from the type map based on the given oid and format codes.
Returns the removed coder object.