I've got a database with 3 users, each one has to have permissions over different tables:

1. One have to have ONLY SELECT permission to all tables but 3.
2. Another one have to have ONLY INSERT permissions to 3 or 4 tables.
3. Another one have to have all permissions on all tables.

I don't have problems with the third one, but the first two have been a nightmare.

Right now number one is defined as db_datareader, deny permissions on SELECT for the three tables who should not, and SELECT WITH GRANT to all other tables.

But when accessing to SQL Server from the web aplication it says that it don't have SELECT permissions over one of the tables which it should.

I've given the permissions from the table properties and user properties dialog box.

What i'm doing wrong?

is the application connecting to the sql server as the 3 users and their credentials or a different user name and password in a connection string somewhere?