As a rule, use standard generated Rules Engine SQL statements wherever possible, use joined columns rather than GUI-designed fields, and use Main Queries and Extra Queries rather than manually programmed behavior.
This is particularly important in the light of maintenance of the application and the possibility of making changes to it at low cost.
Moreover, using standard generated SQL statements where possible will also generally improve performance. This is because cursors are likely to be re-used, and because a number of customized or preset strategies for optimizing SQL statements are more likely to yield effect on default generated SQL statements than on complex customized joins and subqueries.
This section presents some detailed tips to improve the performance regarding querying.