Where to apply the test
The test can be applied in four ways: All rows -- check that the expression is true for every row in the source table. At least one row -- check that the expression is true for at least one row in the source table. No rows -- check that the expression is false for every row in the source table. Once -- check that the expression is true, regardless of the number of rows in the source table.
The expression to check is true
The Check evaluates this expression to ensure that it is true.