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How to add not null Column in existing table in SQL Server 2005?
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asked Dec 17 '10 06:12
You can add a not null column at the time of table creation or you can use it for an existing table. In the above table, we have declared Id as int type that does not take NULL value. If you insert NULL value, you will get an error. Here is the query to add a not null column in an existing table using alter command.
We can add NOT NULL constraint on multiple columns in one table. NOT NULL constraint allows duplicate values. If we defined a column as NOT NULL while inserting or updating values on table, we must and should give value to that specified column. Not Null Constraint allow duplicate values.
To add not null constraint to an existing column in MySQL, we will use the ALTER command. This is a type of validation to restrict the user from entering null values.
How to add not null column to the existing table? explain. alter table your_table add(new_column_name NUMBER default 0 not null);
You will either have to specify a DEFAULT, or add the column with NULLs allowed, update all the values, and then change the column to NOT NULL.
ALTER TABLE <YourTable> ADD <NewColumn> <NewColumnType> NOT NULL DEFAULT <DefaultValue> Choose either:
a) Create not null with some valid default value
b) Create null, fill it, alter to not null
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