# Limit user choices in a combobox

**URL:** <https://forum.kirupa.com/t/limit-user-choices-in-a-combobox/268131>\
**Category:** programming\
**Created:** [August 10, 2008, 1:19pm UTC](https://forum.kirupa.com/t/limit-user-choices-in-a-combobox/268131 "2008-08-10T13:19:29Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Slider16](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Slider16](https://forum.kirupa.com/u/Slider16)\
**Post date:** [August 10, 2008, 1:19pm UTC](https://forum.kirupa.com/t/limit-user-choices-in-a-combobox/268131/1 "2008-08-10T13:19:29Z")

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I am starting a C# Winforms application where part of the main data entry form consists of seven comboboxes allowing the user to select a single item from each combobox, or leave the column blank if they so choose. I am representing the choices in the comboboxes as text, of course, but in my main table I will store the unique ID (int) that they choose.

I want the user to be able to maintain the lists that populate the seven comboboxes. What is the best database design for doing this? I have tried two different methodologies so far. First I created seven tables, one for each combobox, since each one has a different meta data type. The tables had three columns - ID, Name, and Description. The ID was the primary key that I related to the main table.

Then I thought it would be better to combine all seven lists into one “meta data” table by simply adding a TYPEID column to the table. That made designing the form to maintain the meta data lists a bit easier. However, when I try to relate my “metadata” table to my main table ON MULTIPLE COLUMNS AND enforce referential integrity I get the following error in the SQL Designer and the VS Dataset Designer:

" Introducing FOREIGN KEY constraint ‘FK\_docs\_status’ on table ‘docs’ may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. "

I am not allowing the user to modify the uique ID in the metadata table. However, when the user deletes one of the metadata “status” items, I want to “Set Null” the status column in my docs table.

What is the best design pattern? Should I maintain seven different “metadata” tables?

Thank you.