Unique Index on Array in MongoDB

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0

Say we have a collection of documents similar to this:

{
  foo: "Bar",
  foos: [1, 2, 3]
}

I would like to define a unique index such that no document identical to this one can be inserted into the database.

db.stuffs.ensureIndex({ foos: 1 }, { unique: true })

Seems to block any document containing a foos array with any intersection, eg. if the document above was already in the database, then

{
    foo: "Bar",
    foos: [ 1 ]
}

Would also be blocked.

> db.stuffs.ensureIndex({ foos: 1 }, { unique: true })
> db.stuffs.insert({ foo: "Bar", foos: [ 1, 2, 3 ]})
> db.stuffs.insert({ foo: "Bar", foos: [ 1 ]})
E11000 duplicate key error index: test.stuffs.$foos_1  dup key: { : 1.0 }

I would like to be able to make insertions of [ 1, 2 ], [ 2, 1 ], [ 1, 3 ], etc. but not two [ 1, 2 ]

asked 44 secs ago

dave

48

Unique Index on Array in MongoDB