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I add a NOT NULL constraint on my NVARCHAR column so it couldn't allow any empty values. but unfortunately SQL Server deals with NULL and empty values as two separate values!
So how do I make the server throw an exception when inserting nothing to the column?
I'm thinking using the constraint CHECK but I didn't find any samples when used with NVARCHAR columns!
813
Allowing NULL values on a column is normally done to allow the absense of a value to be represented. When using NVARCHAR there is aldready a possibility to have an empty string, without setting the column to NULL .
The NOT NULL constraint guarantees that the column will have a value for each record. In other words, the column will not allow empty values to be stored in it.
The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.
NVARCHAR is a locale-sensitive character data type that allows storing character data in variable-length fields as strings of single-byte or multibyte letters, numbers, and other characters supported by the code set of the necessary database locale.
You could add a check constraint that ensures that the string isn't empty.
CREATE TABLE [dbo].[Foo]( [bar] [nvarchar](50) NOT NULL ) ALTER TABLE [dbo].[Foo] WITH CHECK ADD CONSTRAINT [CK_Foo] CHECK (([bar]<>N'')) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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