Is there an official name for the many-to-many relationship table in a database schema?
Most of the projects I've worked on have required many-to-many relationships in the database schema. For example, you might have the concept of Users and Groups, and the database might contain a table User, a table Group, and a table UserGroup to relate the two.
I'm interested in the conceptual name of the UserGroup table in that example.
I've grown accustomed to calling them "swing tables" because that's how I learned it, but I haven't heard other people use that term in a while.
Instead, I've heard all of the following (including some new ones, thanks to all of you!):
- Association table
- Bridge table
- Cross-reference table
- Gerund (E.F. Codd, creator of the relational model, may prefer this)
- Intersection tables
- Join table (most search results on Google...see answer below)
- Junction table (Wikipedia favors this one)
- Link table (Fowler likes this one)
- Many-to-many relationship tables
- Map table
- Reference table
- Relationship table
- Swing table
Is there an official name for this kind of table, with a source to back its official-ness?
Answer
I call it a cross-reference table.
Some may not consider this an official term, but it's certainly a popular one. I mean, you'll find plenty of relevant results in Google if you search for it. The other thing I like is that it can be easily abbreviated "xref" and then used in your table naming scheme, e.g. "table1_xref_table2". That'll get everyone on your team calling it the same thing.
UPDATE:
Wikipedia calls it a junction table. It's strange that I've never heard that term but I suppose different circles call it different things. As we're finding out -- there is no single official answer.