从所有表中删除外键关系 [英] Remove Foreign Key Relationships From All Tables

问题描述

我有一个数据库有几个表。许多表中都有外键约束的字段。我想截断表，然后用新的数据重新填充它们，而且我还想取掉外键，因为一些关系已经改变了。基本上，我想再次从头开始建立FK约束。如何从所有表中删除当前的FK约束？您可以使用information_schema进行游戏。
看看这个页面

http://dev.mysql.com/doc/refman/5.0/en/key-column-usage-table.html

$ pre code $ select $ c $ select $（$'$'$'$ $ $'
where constraint_schema ='your_db'and referenced_table_name ='table_name';

然后运行生成的输出。

你可以做类似的事情来截断所有的表。

$ $ $ $ $ $ $ $ $ select select（'truncate'，table_name，';'）
from information_schema.tables
where table_schema ='your_db'and table_type ='base table'

这个将截断指定数据库中的所有表。所以小心使用它。

I have a database that has several tables. Many of the tables have fields with foreign key constraints. I want to truncate the tables and then repopulate them with new data, and I also want to take off the foreign keys, as some of the relationships have changed. basically, I want to build the FK constraints up from scratch again. How can I remove the current FK constraints from all tables?

解决方案

You can play with the information_schema. Take a look at this page

http://dev.mysql.com/doc/refman/5.0/en/key-column-usage-table.html

select concat('alter table ',table_name,' drop foreign key ',constraint_name,';') 
from information_schema.key_column_usage
where constraint_schema = 'your_db' and referenced_table_name = 'table_name';

then run the output generated.

You can do something similar in order to truncate all tables.

select concat('truncate ',table_name,';') 
from information_schema.tables
where table_schema = 'your_db' and table_type = 'base table'

this one will truncate all tables within the specified database. So use it with care.

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