Question

我们支持的各种客户运行的脚本的一部分添加了外键，但是在运行脚本的这一部分时我不想添加其中一个外键，因为有些客户在他们的设置中没有这个。如何从下面的代码中删除FK6。我在下面的外键FK6上尝试了DROP但是语法错误。

IF OBJECT_ID('FK2') IS NULL
BEGIN
ALTER TABLE [table_1] ADD
  CONSTRAINT [FK2] FOREIGN KEY
  (
     [reason_gen]
  ) REFERENCES [table_1] (
     [field_1]
  ) NOT FOR REPLICATION,
  CONSTRAINT [FK3] FOREIGN KEY
  (
     [field_2],
     [field_3]
  ) REFERENCES [table_2] (
     [field_4],
     [field_5]
  ) NOT FOR REPLICATION,
  CONSTRAINT [FK4] FOREIGN KEY
  (
     [res_code_gen]
  ) REFERENCES [table_3] (
     [field_6]
  ) NOT FOR REPLICATION,
  CONSTRAINT [FK5] FOREIGN KEY
  (
     [field_7],
     [field_8]
  ) REFERENCES [table_4] (
     [field_7],
     [field_8]
  ) NOT FOR REPLICATION,

 ALTER TABLE [table_1] DROP
 CONSTRAINT [FK6] FOREIGN KEY
  (
     [field_9]
  ) REFERENCES [ftable_5] (
     [field_10]
  ) NOT FOR REPLICATION
END

Answer 1

删除外键的语法只是：

ALTER TABLE [table_1] DROP CONSTRAINT [FK6]

Answer 2

这是哪个数据库？ Oracle，MYSQL，SQL Server？

对于Oracle，语法为：

ALTER TABLE table_name
drop CONSTRAINT constraint_name;

删除外键约束（如果不存在）

2 个答案: