blob 字段Data too long for column 'details

liyihongcug

但无论什么2进制字段 ，存入文件大小总是有限制
ySQL有四种BLOB类型:

　　·tinyblob:仅255个字符

　　·blob:最大限制到65K字节

　　·mediumblob:限制到16M字节

　　·longblob:可达4GB

　　在每个MySQL的文档(从MySQL4.0开始)的介绍中,一个longblob列的最大允许长度依赖于在客户/服务器协议中可配置的最大包的大小和可用内存数。

　　你可能对在BLOB中存储大型文件非常谨慎，但是请放心使用，MYSQL提供了这样的灵活性！最大包的大小可容易地中的在配置文件中设置。例如:

一,Windows通过文件my.ini (在系统盘)
[mysqld]
set-variable = max_allowed_packet=10M

二,linux通过etc/my.cnf
[mysqld]
max_allowed_packet = 16M

　　你能指定几乎任何你需要的大小。默认是1M。
: 可以知道  尽管 ·longblob:可达4GB，但是max_allowed_packet 这个是实际限制了你的文件大小
你看看你本地my.ini或者my.cnf的  max_allowed_packet 的大小
所以每个存入字段的大小必须小于max_allowed_packet

liyihongcug

Ticket #4164 (closed defect: worksforme)

Opened 4 years ago

Last modified 4 years ago
Can't create a LongBlob column from migration
Reported by:         squeegy@beautifulpixel.com         Assigned to:         David
Priority:         normal         Milestone:        
Component:         ActiveRecord         Version:         1.0.0
Severity:         normal         Keywords:        
Cc:                        
Description ¶

At least under MySQL migration can't create a LongBlob or MediumBlob column. The following code simply create a binary column that is too small for a lot of uses.

create_table :files do |t|
  t.column :data, :binary, :null => false
end

I'm not sure about the best way to handle it though. Maybe the MySQL adapter could clue in a high limit. Or perhaps the type could be one of :binary, :binary_medium, :binary_large.
Change History
03/09/06 21:14:07 changed by david ¶

    * status changed from new to closed.
    * resolution set to worksforme.

In MySQL 4.1 and above, you can specify the length on a blob or text by using size. It'll automatically expand to the right type. Example:

create_table :files do |t|
  t.column :data, :binary, :null => false, :size => 400000
end

09/01/06 00:16:08 changed by anonymous ¶

    * severity changed from trivial to normal.
    * cc deleted.
    * component set to ActionMailer.
    * summary changed from Can to Can't create a LongBlob column from migration.
    * priority set to normal.
    * keywords deleted.
    * type changed from task to defect.

01/07/07 10:55:05 changed by bitsweat ¶

    * component changed from ActionMailer to Activ

liyihongcug

报告错误

[2011-07-19 11:51:08,446 ERROR] query.InsertSubscriptionUpdateSQLQuery - com.mysql.jdbc.exceptions.jdbc4.MySQLDataException: Data truncation: Data too long for column 'participaIds' at row 1

Query being executed when exception was thrown:

update
java.lang.RuntimeException: com.mysql.jdbc.exceptions.jdbc4.MySQLDataException: Data

truncation: Data too long for colum

个BLOB或TEXT列，最大长度为65535(2^16-1)个字符。

MEDIUMBLOB
MEDIUMTEXT
一个BLOB或TEXT列，最大长度为16777215(2^24-1)个字符。

LONGBLOB
LONGTEXT
一个BLOB或TEXT列，最大长度为4294967295(2^32-1)个字符。