Mysql - why use unsigned columns?

[Antivirus]

I have been looking at many hacks, and notice that some tables have their columns unsigned, and others dont. I know that when a column is unsigned, it starts counting at 0, as opposed to negatives... but is that simply all that should determine assigning a column as unsigned??? the fact that there is simply no need for negative intergers in my scripts?

???

Originally Posted by Antivirus

I have been looking at many hacks, and notice that some tables have their columns unsigned, and others dont. I know that when a column is unsigned, it starts counting at 0, as opposed to negatives... but is that simply all that should determine assigning a column as unsigned??? the fact that there is simply no need for negative intergers in my scripts?

???

UNSIGNED is normally used with AUTO_INCREMENT, (which is used to create a sequence of unique identifiers), because the values of AUTO_INCREMENT are always postive integers.

[Antivirus]

Originally Posted by Danny.VBT

UNSIGNED is normally used with AUTO_INCREMENT, (which is used to create a sequence of unique identifiers), because the values of AUTO_INCREMENT are always postive integers.

I see... thanks Danny!

[Paul M]

Originally Posted by Antivirus

I have been looking at many hacks, and notice that some tables have their columns unsigned, and others dont. I know that when a column is unsigned, it starts counting at 0, as opposed to negatives... but is that simply all that should determine assigning a column as unsigned??? the fact that there is simply no need for negative intergers in my scripts?

???

If you don't use negative number then it doubles the maximum value the column can hold, e.g. for a 2 byte integer, signed max = 32767, unsigned = 65535.

[Antivirus]

thanks for that info as well Paul