On 6/24/2011 1:58 PM, logan...@gmail.com wrote: > Sorry, but seems like I'm missing something here. > > From my understanding it looks like for Integer ID columns that are PK > SQLite doesn't generate any indexes. Is this true?
It's true in a narrow technical sense, but it doesn't matter in practice. In SQLite, data is organized in B-trees. Each table and each index is a B-tree. For an index, the key into that B-tree is the set of fields the index is built on. For a table, each row has a unique integer identifier, usually referred to as RowId, which serves as a key into the table's B-tree. Looking up a row in the table by its RowId is as fast as looking up an index entry by its key, because it's really the same operation. When you declare a column as INTEGER PRIMARY KEY, SQlite simply makes it an alias for an already-existing, always-present RowId column. Again, the table itself essentially acts as an index on this column, no additional external data structure is necessary. -- Igor Tandetnik _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
