You can create data validation tests for a single-table constraints to validate the values in columns of a table. For example, you can compare the column values against a constraint value or verify that all values in a column are not null.
You can add the following types of tests for single-table constraints:
Includes COUNT, COUNT_DISTINCT, COUNT_ROWS, MIN, MAX, AVG, and SUM.
Includes FORMAT, UNIQUE, NOT_NULL, and NOT_BLANK.
Most single-table constraints allow you to enter a constraint value for the test. The constraint value defines the value or values to which you want to compare the values in a field. For example, you might want to verify that a SALARY field contains values greater than $10,000. Enter the minimum salary as the constraint value.