MySQL trunc 规格严格

Hi
  I am trying to insert my file content to the Mysql 5.0, i am trying
to insert 1000 files, but when inserting some of the file, i got an
exception, why?

com.mysql.jdbc.MysqlDataTruncation: Data truncation: Data truncated for
column 'content' at row 1
    at
com.mysql.jdbc.SQLError.convertShowWarningsToSQLWarnings(SQLError.java:709)
    at
com.mysql.jdbc.MysqlIO.scanForAndThrowDataTruncation(MysqlIO.java:3461)
    at
com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1198)
    at
com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:677)
    at
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1357)
    at
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1274)
    at
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1259)

The file that cause the exception is arround 85KB. and here is the
table structure:

CREATE TABLE `articles` (
`id` int(11) NOT NULL auto_increment,
`major` text NOT NULL,
`minor` text NOT NULL,
`author` text NOT NULL,
`url` text NOT NULL,
`topic` text NOT NULL,
`content` text NOT NULL,
`filename` text NOT NULL,
`filesize` int(11) NOT NULL default '0',
`date` datetime NOT NULL default '0000-00-00 00:00:00',
`rank` int(11) NOT NULL default '0',\n  PRIMARY KEY  (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=gb2312

thanks
from Peter (cmk128@hotmail.com)

Reply to this Message

David Harper - 28 Oct 2006 07:44 GMT

> Hi
>    I am trying to insert my file content to the Mysql 5.0, i am trying
[quoted text clipped - 34 lines]
> `rank` int(11) NOT NULL default '0',\n  PRIMARY KEY  (`id`)
> ) ENGINE=MyISAM DEFAULT CHARSET=gb2312

The online manual,

  http://dev.mysql.com/doc/refman/4.1/en/index.html

is your friend.

The manual explains the limitations of the different data types:

  http://dev.mysql.com/doc/refman/4.1/en/storage-requirements.html

A TEXT column can store no more than 65534 bytes (that's 2^16 minus the
two-byte length field).

The manual page which describes BLOB and TEXT types,

  http://dev.mysql.com/doc/refman/4.1/en/blob.html

says the following:

  "If you assign a value to a BLOB or TEXT column that exceeds the data
   type's maximum length, the value is truncated to fit. If the
   truncated characters are not spaces, a warning is generated."

85K is larger than 65534, so you get an exception.

The solution is to declare the "content" column as a MEDIUMTEXT if you
can be sure that your files will never exceed ~ 16 megabytes in size, or
as a LONGTEXT if you think you may need to store files larger than 16
megabytes at some point in the future.

David Harper
Cambridge, England