Creating a Check Constraint

Creating a check constraint specifies a condition that any value must pass before it is inserted into the table.

A check constraint specifies a condition that any value must pass before it is inserted into the table. You can can create a check constraint at the table or column level. Column-level check constraints reference a single column. Table-level check constraints apply to the entire table.

In the Perspective Resources view, select the server on which the table resides, then click the drop-down arrow next to the server name and select Administration Console.
In the left pane of the Administration Console, expand ASE Servers > Schema Objects > Tables, then choose one of the following:
- User Tables
- Proxy Tables
Select a table for the new check constraint.
Select Properties.
From the Table Properties window, select Check Constraint > New.
You see the Add Check Constraint wizard.
Enter a name for the check constraint.
Enter an expression that defines the constraint.
For example, salary > 0. The comparable command line syntax using alter table is:
```
alter table sample.dbo.employee
add constraint test_const
CHECK  (salary > 0)
```
(Optional) Click Summary to verify the check constraint expression.