Create a index in PostgreSQL
Indices are created in an existing table to locate rows more quickly and efficiently. It is possible to create an index on one or more columns of a table, and each index is given a name. The users cannot see the indexes, they are just used to speed up queries. Updating a table containing indexes takes more time than updating a table without, this is because the indexes also need an update. So, it is a good idea to create indexes only on columns that are often used for a search. CREATE [ UNIQUE ] INDEX name ON table [ USING method ] ( { column | ( expression ) } [ opclass ] [, ...] ) [ TABLESPACE tablespace ] [ WHERE predicate ] Parameters UNIQUE Causes the system to check for duplicate values in the table when the index is created (if data already exist) and each time data is added. Attempts to insert or update data which would result in duplicate entries will generate an error. name The name of the index to be created. No schema name can be included here; the index