2 comboboxes - 1 for tables in a DB, the other - datafields in a table

Question

Dear All,
I have a database with 5 tables with one column. I want to use 2 comboboxes - first to have the names of the tables and second to have the fields (without primary key) of the tables so when I choose one field from the second combobox,  I can see the data written in it.
Please, help me to do this.
Regards,
Trifon.