[wp-hackers] BIGINT(20) ... was: Is there a limit to the number of sub categories?

[Eric Marden]

>> It's a BIGINT with a 20 digit limit. ;)
>>
>
>
> The "BIGINT(20)" specification isn't a digit limit.  It just means  
> that when
> the data is displayed, if it uses less than 20 digits it will be  
> left-padded
> with zeros. 2^64 is the hard limit for the BIGINT type, and has 20  
> digits
> itself, hence BIGINT(20) just means everything less than 10^20 will be
> left-padded with spaces on display.  This is kind of getting off topic
> though, so...

Not to keep riding a dead horse, but I wanted to chime in on this  
quickly.

Here's the full column definition:

`term_id` bigint(20) NOT NULL auto_increment

The '20' is the maximum display width. However, this does NOT limit  
the range of values that can be stored in this column, which for  
bigint is: -9223372036854775808 to 9223372036854775807

If its unsigned (which this one is not), a bigint has this range: 0  
to 18446744073709551615

If you specify zerofill as one of the options in the column  
definition, values will be left-padded with zeros. Displaying the  
value without zerofill will left-pad with spaces.

More info here:
http://dev.mysql.com/doc/refman/5.0/en/numeric-type-overview.html
http://dev.mysql.com/doc/refman/5.0/en/numeric-types.html



-e