The most difficult was Tuning and Optimizing Data Access questions (I've\nreceived the least sectional rating there). It's no wonder in it because all\narticles in BOL on this subject are recomendational. Any optimization is\nactually an art.\nFor example, if you want to ensure that indexes you have created are\nused by query optimizer you can use two ways:\n- ask Index Tuning Wizard to suggest creating of other indexes\n- use SET SHOWPLAN option in Query Analizer\nIn exam I had to choose only one answer from theese options. I'm still\ndon't know the right one.\nOr: a table had been heavily accessed with INSERT, UPDATE and DELETE\nqueries. That means that:\n- their B-tree became unbalanced\n- existing indexes became defragmented\n- statistics on columns became out of date\nTo tune better performance you can choose all of the following\nstatements: DBCC DBREINDEX, DBCC INDEXDEFRAG and UPDATE STATISTICS, but exam\nquestion has only one right question.