[Resolved] mysql error due to 'overhead'

[artist-ink]

hello,

i was getting a error with mysql last night.

i was using php to enter some items into my database. it had been workign for a few days, then all of a sudden, it stopped working. up to that point, i had entered 127 items.

i logged into my database, through phpmyadmin to see what kind of error was happening.

this is what i got:

Error

SQL-query : 

INSERT INTO Link_Info( Link_ID, UserName, Link_Display, Link_Description, Link_URL, Category )
VALUES (
'', 'user1, 'Artist-Ink.com', 'Free online gallery for artists, musicians and writers. Join for Free.', 'http://www.artist-ink.com', 'Arts & Humanities'
)

MySQL said:
#1062 - Duplicate entry '127' for key 1 

key 1 or Link_ID was set up as a tinyint with a lenght of 8 and is auto incremented.
i took a look at the tab that shows the structure of your tables, and in red, under 'space usage' i saw 'OVERHEAD 748 bytes' or something like that. i clicked on optomize table and this disappeared.

after that i tried to enter some info, through phpmyadmin, and it still didn't work.

what i ended up doing, to get it to work was change Link_ID to int(200)

does anyone know why i was getting this error?
how can i prevent it in the future?
is int(200) ok for this field, or should i change it to something else?

thanks for your help.

[devinemke]

the maximum value for an unsigned TINYINT is 127. read up on mySQL Numeric Types.

[bradgrafelman]

Indeed, reading up on those types will help.

You can probably leave the 200 out on 'int()', as it's optional to specify the width. You might not even need to use such a large number as an integer; looking at the link divine gave you, you'll notice that 'smallint's can go up to 65535, assuming you don't need negatives. 'mediumint's can go up to 16777215, again assuming you don't need negatives.

If you want to remain efficient or use less space, take a look at using 'unsigned smallint' or 'unsigned mediumint' to fit your needs; otherwise, using an 'int' is just fine.

EDIT: Woops, didn't notice the [Resolved] tag. :o