Question

Is there a way to have a table definition that bases its Non-Duplication on two fields?

By this i have 3 columns
gid, cid, price

Criteria:

• There can only be 1 cid for 1 gid
• There can be multiple cid‘s as long as there are multiple gid‘s and criteria 1 is not violated

I basically want to have the restriction in the Table Design, if possible. Not sure if its possible just figured i would ask.

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Edit (2010-08-27 11:18am CST)

Ok a little clarification, i have two indexes as well, one on gid and other is on cid, can i have the two indexes determine Uniqueness? The table is basically a Join table since the two tables drawn in have a 1-Many relationship, in so far as their counterpart is unique to its id.

Table/Indexes declaration:

• gid {Numeric:Long} (Primary: No, Unique: No, Ignore Nulls: No) [FK]
• cid {Numeric:Long} (Primary: No, Unique: No, Ignore Nulls: No) [FK]
• price {Numeric:Single}

Usage:

• cid 1-Many gid
  • cid is derived from tblCat (as the PK)
• gid 1-Many cid
  • gid is derived from tblGrp (as the PK)

Answer 1

There is no difficulty in creating multi-field indexes in MS Access. You can simply click the indexes button (lightning flash) and choose what you need.