databases/cego: upgrade 2.44.14 -> 2.45.0

• Added table alias feature to grammar definition. Table aliases allow alternate table name and attribute name definitions for a table ( create alias ... )
• Added classes CegoAliasObject and CegoAttrAlias for table alias handling
• Implemented base semantic actions for creating, listing and describe alias objects ( still no usage )
• In CegoDistManager::registerObjects, added registration for fkey, check, trigger and alias
• Added alias mapping for insert, update and delete queries ( CegoQueryHelper::mapAliasPredicate still to implement )
• Basic alias mapping for select works, here's a sample SQL script drop if exists table t1; list alias; desc alias a1; drop if exists alias a1; create table t1 ( a int, b string(30)); create alias a1 on t1 ( a as ax, b as bx ); insert into a1 ( ax, bx ) values ( 1, 'XXX'); insert into a1 ( ax, bx ) values ( 2, 'YYY'); insert into a1 ( ax, bx ) values ( 3, 'ZZZ'); select ax from a1;
• More work on table alias handling. Now works with more sophisticated select queries ( e.g. select ax from a1 aa where aa.ax = 1; ) For this, some fixes had to be done in CegoContentObject, since the the table alias attribute ( _tabAlias ) was not setup in constructor and other methods
• Added alias and trigger xml export and import feature ( trigger xport was still not implemented ) Fix in CegoDbThread::loadObjects for trigger reload, instead of triggerList.Next(), triggerList.First() was called, which result in an infinite loop in case of existing trigger objects
• Added trigger and alias object handling to CegoXPorter binary export and import

Submitted by: Bjoern Lemke <lemke@lemke-it.com>