MySQL too long varchar truncation/error setting

问题:

I have two MySQL instances. The 1st one truncates strings on insert when data is too long. The 2nd one raises an error:

ERROR 1406 (22001): Data too long for column 'xxx' at row 1

I want the 2nd one to truncate the data as well. Is there any MySQL setting to manage this behavior?

回答1:

You can disable STRICT_TRANS_TABLES and STRICT_ALL_TABLES. This allows the automatic truncation of the inserted string.

Quote from MySQL Documantation.

Strict mode controls how MySQL handles invalid or missing values in data-change statements such as INSERT or UPDATE. A value can be invalid for several reasons. For example, it might have the wrong data type for the column, or it might be out of range. A value is missing when a new row to be inserted does not contain a value for a non-NULL column that has no explicit DEFAULT clause in its definition. (For a NULL column, NULL is inserted if the value is missing.)

Reference: MySQL Server SQL Modes

回答2:

If strict SQL mode is not enabled and you assign a value to a CHAR or VARCHAR column that exceeds the column's maximum length, the value is truncated to fit and a warning is generated. For truncation of nonspace characters, you can cause an error to occur (rather than a warning) and suppress insertion of the value by using strict SQL mode. See Section 6.1.7, “Server SQL Modes”.

How you can change it: http://dev.mysql.com/doc/refman/5.7/en/sql-mode.html

---

Found two ways to disable strict mode:

1. add below to my.cnf

   sql-mode="NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"

2. way is using mysql console.

   SET @@global.sql_mode= '';

Please test them before running on production environment.

回答3:

if you use cpanel ,

replace

sql-mode="NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"

into /usr/my.cnf

to

sql-mode=""

run

/etc/init.d/mysql restart