为什么此ALTER TABLE MYSQL查询未执行（返回false）？ 语法看起来正确

Question

I am running dynamic queries based on adding removing fields to categories. Here is an example query:

ALTER TABLE se_classifiedvalues 
  ADD classifiedvalue_402 varchar(250) NOT NULL default ''

MYSQL isn't complaining about syntax but returns false when I var dump the query. When I threw that query into phpMyAdmin and tried to execute the sql it threw this:

#1118 - Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. You have to change some columns to TEXT or BLOBs

any one have any idea what I can do to fix this?

thanks

Answer 1

How many columns are in this table already? 402? (I hope not). MySQL has a limit as to the amount of data (bytes) it can store in one row of a table, and it looks like you've reached that limit.

Edit: Here's a link on the MySQL site where you can read about data limits: http://dev.mysql.com/doc/refman/5.0/en/column-count-limit.html

I think you need to re-think your data structures.

Side question: Are you using ExpressionEngine?

Answer 2

Make the total size of all columns less than the limit 65,535 bytes. Note that UTF8 columns count as 3 bytes per character.

65,535 is the maximum row size in bytes.

From MySQL :

The effective maximum length of a VARCHAR in MySQL 5.0.3 and later is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used.