Make existing column primary key

[dandot]

I have an existing column that id like to make into a primary key. What is the code for that?

 

[gmmastros]

In order to make a column be the primary key, you must first make sure you do a couple things.

1. Primary Keys must be unique, so you'll need to make sure there are no duplicates in that column.

2. You need to make sure there are no nulls in the column.

3. You also must make sure that the database doesn't allow nulls.

To make the column not accept NULLS...

Alter Table [!]TableName[/!] Alter Column [!]ColumnName[/!] (datatype) NOT NULL

Of course, you'll need to change the data type to match the data type of the column.

Then....

Alter Table [!]TableName[/!] ADD CONSTRAINT [!]ContraintName[/!] Primary Key Clustered ([!]ColumnName[/!])




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