MySQL performance tip No. 3: Rows can be served from indexes InnoDB can find and actually serve rows directly from indexes, whereas a secondary key points to the primary key and the primary key ...

Duplicate and Ignore on MySQL Inserts. MySQL table primary keys and unique indexes prevent multiple rows with the same index from being added to the table. If you try to insert a duplicate row ...

Any attribute that is uniquely identify a row in a table is candidate key (primary key) for the table. We select one of the candidate key as Primary key. All candidate keys which are not chosen as ...

Can you do a foreign key within a single table, though? I've only ever seen foreign key constraints tying a field in one table to a field in another table.

Now, this app uses surrogate keys extensively (Django doesn't allow composite primary keys and encourages the use of surrogates heavily). For the first migration scripts I've tentatively skipped ...