no check table check when inserting into the Z table

Hi

I have a z table and i have put a check table for that say z table2 .

Now when i try to insert entries in se11 in Z table, it rightly does not allow me to insert the records if the key field value is not available in z table 2

But when i try to insert using modify statement in the prgoram it allows me to insert the records in z table even though corresponding records are not there in the z table 2 .

is this correct ??