How to ensure that a field in a document is unique in ArangoDB?

Question

I had created a collection in ArangoDB and need to say that one field is unique. For example I need to say that in 'user_table' 'email' is unique. How to do that?

Answer 1

To ensure uniqueness of a certain attribute in a collection, you can use the ensureUniqueConstraint function for the collection:

db['user_table'].ensureUniqueConstraint("email");

This will create a non-sparse unique index on attribute email .

If email is an optional attribute, you may want to go with:

db['user_table'].ensureUniqueConstraint("email", { sparse: true });

As @CoDEmanX mentioned, it's also possible to use the more general ensureIndex method and specify index type and uniqueness as parameters:

db['user_table'].ensureIndex({ fields: ["email"], type: "hash", unique: true, sparse: true });