Query performance

Query performance and optimization is not always being regarded as an important issue, but most of the time it is. Cost of query may not show difference in startup stages of a system but in the long term it affects system performance significantly. So while creating a view, discoverer report or forms select, costs should be evaluated and optimized. First thing to do in selects is finding right columns to match (usually primary and foreign keys) and using indexes if exist. If not exist creating an index may affect dramatically. Using numbers while matching tables, using sub queries, avoiding full table scans are other tips to remember. Also using SQL instead of PL-SQL may reduce time because it saves the time database requires for transacting in PL-SQL mode.
In Forms design there is a difficult but useful option; folder structure. It provides better functional qualifications in addition to better performance provided by its query method.