
Practice #6: Conditional Filtering by Enumerated Field–A Lightweight Solution to Speed up Queries by Dumping Data to Files
An enumerated field has only several values. The format of filtering condition specified on an enumerated field (f) can be f =v1 or f=v2 or…, f !=v1 and f !=v2 and…, in or not in. The database compares f with n values. When the data table is large, there is a great number of comparisons,…