Comments on: Enum to Int Conversion in MySQL

By: sullivat

sullivat — Wed, 02 Aug 2006 04:39:48 +0000

Storing a boolean as an enum with two ints (well, you can only have strings in a mysql enum, but you can pretend they are ints) lets you toggle the value of the bool really cool-like:

> create table mytable ( george enum(’0′, ’1′) );
> insert into mytable values (’0′);
> update mytable set george = binary ( george = 1 );
> select * from mytable;
{ ‘george’: ’1′ }
> update mytable set george = binary ( george = 1 );
> select * from mytable;
{ ‘george’: ’0′ }

By the way, I named the column “George” in honor of George Boole, the inventor of Boolean algebra.

To George:

Thanks.

By: morgamic

morgamic — Mon, 19 Jun 2006 16:53:17 +0000

Say that to my face!

By: Fred

Fred — Mon, 19 Jun 2006 16:47:47 +0000

Yeah, it also helps in case you want to have more than 2 boolean states: true, false, maybe, unsure, uncertain, certain, and pretty sure.

By: morgamic

morgamic — Wed, 14 Jun 2006 08:19:09 +0000

Wise words, Fred — will remember that next time I change how a Boolean is stored.

By: Fred

Fred — Wed, 14 Jun 2006 04:48:29 +0000

What I usually do when I convert the data type of a column: I make a new column with the right type, do an update-and-convert command over the whole table, shuffling the old data into the new column. Then once that worked, I remove the old column and rename the new one.

That’s a step more, but it doesn’t give you bad surprises.