Tagged with "consistency"

Fun MySQL fact of the day: IGNORE at your own peril

Yesterday, we saw how INSERT ... ON DUPLICATE KEY UPDATE can unknowingly result in not-completely-expected situations. To get around that, you may have thought to use INSERT IGNORE, instead. Often, INSERT IGNORE is used when attempting to insert a row that may already exist. The underlying expectation a ... read more

Fun MySQL fact of the day: a CHECKered past

A Check Constraint is a table constraint, described in SQL-89, that allows a database index to remain consistent based on a specified search criteria or expression. For example, we could ADD CONSTRAINT is_even_ck CHECK(my_int_col % 2 = 0) to ensure that the value of the my_int_col column in every row ... read more