Table maintenance

Hi All,

I am creating a custom table.

1. Can the restriction be applied for only particular users?

If so how?

2. When the data is saved i need to validate the data by cross checking the existing data. How and where can it be done.

Say for e.g there are two fields valid from and valid to.

There should not be two records overlaping the date range.

How do i do it in the table maintenance?

If this is not possible with Table maintenance, then i would have to write a seperate program.

uselful ans will be awarded

thanks