问题描述
有没有办法插入整个记录是唯一的SQL数据库?我知道你可以制作主键和唯一的列,但这不是我想要的。
在不重载数据库的情况下,最好的方法是什么?我已经看到一个子查询,你使用WHERE NOT EXISTS()
我只是想知道最有效的插入记录的方法,以便没有重复的EXACT相同的记录。
提前谢谢!
你知道如何在列上的唯一索引。
只需将所有列应该在一起是唯一的:
在tablename(columnone,columntwo,columnthree)上创建唯一索引foo
;
请注意,需要这样做可能表示您的表格没有被足够的标准化。 p>
Is there a way to insert into an SQL database where the whole record is unique? I know you can make primary keys and unique columns, but that is not what I want.
What is the best way of doing this without overloading the database? I have seen a sort of subquery where you use "WHERE NOT EXISTS ()"
I just want to know the most efficient way of inserting a record so that there are no duplicates of the EXACT same record.
Thank you in advance!
You know how to make a unique index on a column.
Just make that on all the columns that should, together, be unique:
create unique index foo
on tablename(columnone, columntwo, columnthree);
Note that the need to do this may be an indication that your table is not sufficiently normalized.
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