如何从sqlite（3.6.21）表中删除约束？ [英] How do I DROP a constraint from a sqlite (3.6.21) table?

问题描述

我有以下表格：

  CREATE TABLE child（
 id INTEGER PRIMARY KEY，
 parent_id INTEGER CONSTRAINT parent_id REFERENCES parent（id），
 description TEXT）; 
  

如何删除约束？

解决方案

SQLite不支持 alter table drop约束命令。您需要创建一个没有约束的新表，传输数据，然后删除旧表。

我认为类似以下内容应该可以工作：

  CREATE TABLE child2（
 id INTEGER PRIMARY KEY，
 parent_id INTEGER，
 description TEXT 
 ）; 
 INSERT INTO child2（id，parent_id，description）
 SELECT id，parent_id，description FROM CHILD; 
 DROP TABLE child; 
 ALTER TABLE child2 RENAME TO child; 
  

如果不想传输，也可以省略上述所有语句的parent_id。 / p>

I have the following table:

CREATE TABLE child( 
  id INTEGER PRIMARY KEY, 
  parent_id INTEGER CONSTRAINT parent_id REFERENCES parent(id), 
  description TEXT);

How do I drop the constraint?

解决方案

SQLite does not support the alter table drop constraint command. You will need to create a new table without a constraint, transfer the data, then delete the old table.

I think something like the following should work:

CREATE TABLE child2 ( 
    id INTEGER PRIMARY KEY, 
    parent_id INTEGER,
    description TEXT
);
INSERT INTO child2 (id, parent_id, description)
   SELECT id, parent_id, description FROM CHILD;
DROP TABLE child;
ALTER TABLE child2 RENAME TO child;

You could also leave out parent_id from all the statements above if you don't want it transferred.

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