SQLite multicolumn index example. If you create an index that consists of one column, SQLite uses that column as the sort key. In case you create an index that has multiple columns, SQLite uses the additional columns as the second, third, … as the sort keys. SQLite - Indexes. Indexes are special lookup tables that the database search engine can use to speed up data retrieval. Simply put, an index is a pointer to data in a table. An index in a database is very similar to an index in the back of a book. When you create an index on a column, SQLite will create a data structure for that index where each field value has a pointer to the whole row where the value belongs. Then, if you run a query with a search condition on a column that is part of an index, SQLite will look up for the value on the index first. SQLite won't scan the whole table for it.