I have an existing table with data. I have just added a new column but I cannot find how to add a unique constraint on that column. Could someone please advise? Right-clicking and selecting "check constraints" wasn't helpful.
You need to right-click in the table designer and pick Indexes/Keys
:
Then a dialog pops up and you can add a new index to the list of indices (on the left hand side) and define it to be a unique
index:
Do right-click in the table designer and choose Indexes/Keys .
Indexes/Keys window will open. Click the button Add , to create the new index/key, and choose the column to be unique in the Columns property:
In the properties of the new index/key, set Type to Unique Key :
And this is the generated code for the unique constraint:
ALTER TABLE [dbo].[Table_1] ADD CONSTRAINT [IX_Table_1] UNIQUE NONCLUSTERED
(
[myUniqueColumn] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
尝试右键单击并选择“ Indexes/Keys
,添加新索引并将Is Unique
”设置为“是”。
You just Right Click from which column you need to add unique key from your table and you can select the Indexes/Keys
. Then you can add or delete the column which you want to set unique key
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