mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-17 15:43:24 +02:00
9394d62c73
functions. One problem that I have encountered with the function manager is that it does not allow the user to define type conversion functions that convert between user types. For instance if mytype1, mytype2, and mytype3 are three Postgresql user types, and if I wish to define Postgresql conversion functions like I run into problems, because the Postgresql dynamic loader would look for a single link symbol, mytype3, for both pieces of object code. If I just change the name of one of the Postgresql functions (to make the symbols distinct), the automatic type conversion that Postgresql uses, for example, when matching operators to arguments no longer finds the type conversion function. The solution that I propose, and have implemented in the attatched patch extends the CREATE FUNCTION syntax as follows. In the first case above I use the link symbol mytype2_to_mytype3 for the link object that implements the first conversion function, and define the Postgresql operator with the following syntax The patch includes changes to the parser to include the altered syntax, changes to the ProcedureStmt node in nodes/parsenodes.h, changes to commands/define.c to handle the extra information in the AS clause, and changes to utils/fmgr/dfmgr.c that alter the way that the dynamic loader figures out what link symbol to use. I store the string for the link symbol in the prosrc text attribute of the pg_proc table which is currently unused in rows that reference dynamically loaded functions. Bernie Frankpitt |
||
|---|---|---|
| contrib | ||
| doc | ||
| src | ||
| COPYRIGHT | ||
| HISTORY | ||
| INSTALL | ||
| README | ||
| register.txt | ||
PostgreSQL Data Base Management System (formerly known as Postgres, then as Postgres95). This directory contains the development version of 6.6 of the PostgreSQL database server. The server is not ANSI SQL compliant, but it gets closer with every release. After you unzip and untar the distribution file, look at file INSTALL for the installation notes and file HISTORY for the changes. The latest version of this software may be obtained at ftp://ftp.postgresql.org/pub/. For more information look at our WWW home page located at http://www.postgreSQL.org/. PostgreSQL is not public domain software. It is copyrighted by the University of California but may be used according to the licensing terms of the the copyright below: ------------------------------------------------------------------------ POSTGRES95 Data Base Management System (formerly known as Postgres, then as Postgres95). Copyright (c) 1994-7 Regents of the University of California Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies. IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.