User:Leonsp/Changelog for IBM DB2 support

includes/db/DatabaseIbm_db2.php

 * Removed database column name lowercasing kludge -- now using the official way of getting lowercase column names
 * Added reliable way of getting the last insert id -- required by database API
 * Fixed bug where inserted data was always rolled back when the IGNORE flag was passed

maintenance/ibm_db2/tables.sql

 * Stripped out all unused sequence definitions from the database schema -- the current DB2 database schema uses GENERATED BY DEFAULT columns, not sequences

config/index.php

 * Made installation on IBM DB2 more robust
 * Replaced E_ALL with E_ALL | E_STRICT

includes/db/DatabaseIbm_db2.php

 * Enabled DB2_CASE_LOWER option for all connections and statements
 * Enabled DB2_DEFERRED_PREPARE_ON for all statements -- delays statement preparation until execution to reduce database load
 * Enabled DB2_ROWCOUNT_PREFETCH_ON for all statements -- makes db2_num_rows work correctly
 * Cleaned up error handling
 * Cleaned up method signatures
 * Rewrote insertion to use prepared statements -- required for inserting more than 32k of text
 * Insertion will never try to insert a NULL value into a primary key
 * Now relying on implicit casting in DB2 9.7 -- no longer sniffing to see if column is integer or string before adding quotes
 * Implemented actual prepared statement handling -- required for correct INSERT, UPDATE behaviour
 * In install mode, the class will print additional messages to the install bullet scroll
 * Added bitwise operations (BITNOT, BITAND, BITOR)

includes/specials/SpecialAncientpages.php

 * Added skeleton DB2 syntax to the database-specific switch statement

maintenance/convertLinks.inc

 * Made limit clause database-agnostic

maintenance/ibm_db2/README

 * Contents replaced with link to http://www.mediawiki.org/wiki/Manual:IBM_DB2

maintenance/ibm_db2/tables.sql

 * Revised types to better match the MySQL schema
 * All tables names now the same as MySQL -- was using Postgres names before
 * Added some additional indices
 * Added the change_tag, tag_summary, valid_tag, user_properties, log_search, and l10n_cache tables
 * Added several new columns

maintenance/storage/compressOld.inc

 * Made limit clause database-agnostic