Description
int 
pg_field_type_oid ( resource result, int field_number )
   pg_field_type_oid() returns an integer containing the
   OID of the base type of the given field_number in the
   given PostgreSQL result resource.
  
    You can get more information about the field type by querying PostgreSQL's
    pg_type system table using the OID obtained with this function.
    The PostgreSQL format_type() function will convert a
    type OID into an SQL standard type name.
  
Note: 
    If the field uses a PostgreSQL domain (rather than a basic type), it is
    the OID of the domain's underlying type that is returned, rather than the OID
    of the domain itself.