User:Leonsp/Changelog for IBM DB2 support

Changes for 2009-09-23

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

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

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)

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