How to restrict SQL Server from accepting empty string

Question

I have a table in SQL Server which has a constraint like Not null. When I enter new entry if I am not filling anything, SQL Server pops error message preventing Null value.

But once I enter one record and later if I edit that record by just deleting the data in this column, SQL Server is accepting the empty string.

Program logic should handle this, don't allow your program to delete/remove the value and replace with empty if that is not desired. — Mark Schultheiss
– Mark Schultheiss, Commented Apr 9, 2017 at 2:00
Your description does not sound correct. If the column has a NOT NULL constraint, then it is not allowed in the column. Perhaps the value is an empty string '' rather than NULL. — Gordon Linoff
– Gordon Linoff, Commented Apr 9, 2017 at 2:01
Optionally investigate Check constraints. CHECK constraints determine the valid values from a logical expression that is not based on data in another column. — Mark Schultheiss
– Mark Schultheiss, Commented Apr 9, 2017 at 2:08

Richard Schneider · Accepted Answer · 2017-04-09 02:06:52Z

5

You can use a CHECK CONSTRAINT

ALTER TABLE table
ADD CONSTRAINT chkNotEmpty CHECK (LEN(col) > 0 );

edited Apr 9, 2017 at 2:06

answered Apr 9, 2017 at 2:01

Richard Schneider

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Ramesh Kharbuja · Accepted Answer · 2017-04-09 02:18:31Z

1

By UI you can add constraint by following step

1.open the table in Design view
1. Right Click any column and select "Check Constraints"
2. Edit"Expression" and set the minimum lenth of any field as len(desiredField)>=1

edited Apr 9, 2017 at 2:18

answered Apr 9, 2017 at 2:12

Ramesh Kharbuja

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