Pg_similarity

Set of functions and operators for executing similarity queries

pg_similarity is an extension to support similarity queries on PostgreSQL. The implementation is tightly integrated in the RDBMS in the sense that it defines operators so instead of the traditional operators = and <> you can use ~~~ and ! any of these operators represents a similarity function.

pg_similarity has three main components

• Functions a set of functions that implements similarity algorithms available in the literature. These functions can be used as UDFs and, will be the base for implementing the similarity operators;
• Operators a set of operators defined at the top of similarity functions. They use similarity functions to obtain the similarity threshold and, compare its value to a user-defined threshold to decide if it is a match or not;
• Session Variables a set of variables that store similarity function parameters. Theses variables can be defined at run time.