On 4 Jul 2009, at 8:49pm, James Scott wrote: > CREATE INDEX [PK_Sections] ON [Sections] ([Department], [Course], > [Section]); > > In the programming language, I need to refer to the primary key as 1 > field. > Does Sqlite allow a 'calculated field', such as concatenation of the 3 > columns in the PK? Or can I create a View to combine the 3?
SELECT department||course||section FROM sections or SELECT department||course||section FROM sections ORDER BY department,course,section whichever suits you best. You can use '||' to concatenate anywhere an expression is allowed. As usual, it's not your job to work out which index is best: SQLite does it for you. And because of the way SQLite works it will never actually look at the table to find those values: it needs to use the index anyway and will realise it can take the values directly from the index without having to do the extra lookup to get them from the table. Simon. _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
