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ms-accessdatabase-designmany-to-manyrelational-databaselookup-tables

Access 2013 using a lookup field with multiple values

I'm using a database which contains a Staff table and a Groups table, what I'm trying to do is so that each staff member can be a member of many groups and each group can contain multiple staff, many-to-many relationship. I also have a join table connecting the two (below is my table structure). Both the Staff and the Groups table have a one-to-many relationship with the Group Staff table.

Staff Table

Staff ID
First Name
Last Name

Group Table

Group ID
Group Name

Group Staff Table

Group Staff ID - PK
Group ID - FK
Staff ID - FK

What I'm trying to do is in the Groups Table, I have a field called "Members" which should contain all the staff (looked up from the staff table) who are members of the group. I'm using a lookup field to display all the Staff members. The problem is that I can't select multiple staff for each group, which I need to.

If I try and change the lookup field to "Allow multiple values" then it tells me I can't because of the relationship between the Staff and the Group table, but of course I need the relationship to be able to lookup the Staff members.

So how can I make it so I can can have a lookup field in the Group table that allows me to select multiple Staff from the Staff Table? Any help is appreciated.

Solution

  • You can't do it the way you've describe.

    With a Group and Staff table, if you want a many-to-many relationship, you do (as you state) have to have a joining table (GroupStaff). However, you can't really create the relationships on either the Group or Staff tables.

    You have to create new rows in the GroupStaff table. You can do this manually on row at a time, of if I'm creating a an app, I'll generally have a form with two sub forms. The parent form would be bound to Group in this case, and the subforms would be bound to Staff and GroupStaff respectively. You can then add controls (buttons) to add records to the GroupStaff table base on what records were selected in the Group form and the Staff subform.

    The GroupStaff subform would also be filtered to show only the records associated with the group currently on the parent from.