Primary selector

You can right click on any selector (coded pick list) variable of the Master table and mark that variable as the primary selector. The primary selector is used to provide an index onto the data in addition to the URN index built on the unique row identifier of a table.

The primary selector is only defined on the master table and determines the physical sequence of the compressed FastStats database. Any query that includes criteria on the primary selector may be optimised to reduce the number of rows read from the FastStats database, hence increasing the speed of query evaluation. The FastStats administrator can determine whether the benefit of optimised queries is sufficient to justify the overhead of sorting the data during the load process.

Setting the primary selector¶

If a field is marked as the primary selector it will have a green Selector tick box symbol next to it:

If you are unsure which field to choose as the Primary Selector then do not choose one - FastStats will auto-generate a primary selector if one is not specified.