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How many times have you wanted to code something like this? DECLARE @upgrade_ok VARCHAR ( 1 ) NOT NULL DEFAULT 'Y'
CHECK ( @upgrade_ok IN ( 'Y', 'N' ) );
If you're like me, lotsa times. In fact, quite a few times I have coded NOT NULL... on purpose, not by accident. |
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What about FKs, i.e. something like I haven't had such requirement but that works with checks on columns and should then work with checks on local variables... (Note, for columns, one would use a FOREIGN KEY constraint here, I know, but a check with a sub-select to a different table is possible, too, and senseful in some cases where a FK can't be used´). |
I type my variables currently with a DOMAIN. It would be great if the constraints would work in this case too.
CREATE DOMAIN "BOOLEAN" char(1) DEFAULT 'N' check(@column is null or(@column in( 'Y','N') ));
DECLARE @upgrade_ok BOOLEAN;
@TDuemesnil: You can shorten the check - CHECK constraints are only violated when the expression is FALSE, not when UNKNOWN. This is different to search conditions where only expressions that are TRUE get selected. Therefore the "@column is null or "-part can be omitted (though it might be more comprehensible).