CODEWITHSUNDEEP
validationcouchdb
arnoutaertgeerts
arnoutaertgeerts

Reputation: 2322

Validation function to ensure unique field in couchdb

Is it possible to write a validation function to ensure a field of a new document is unique?

Imagine I'm trying to write a validation function that does not allow for two users to have the same email. Every time I create a new user, the validation function will be called and will probably look something like this:

function (newDoc, oldDoc) {
    //How do I get this array to contain the emails of all the users?
    var allEmail;

    if (allEmail.indexOf(newDoc.email) !== -1) {
        throw "This email adress is already taken";
    }
};

How can I fill the array allEmail to contain all emails of the users?

Is it possible to call views in the validation function?

Upvotes: 2

Views: 461

Answers (2)

Sundaramoorthy J
Sundaramoorthy J

Reputation: 148

If the application is in offline, the above suggested solution how will react. Local pouch view can check and return the pouch results alone. There may be a high chance of same value entered from some other end and updated to couch db.

Do you have workaround for this case ?

Upvotes: 0

Kxepal
Kxepal

Reputation: 4679

Not possible. Validation function only operates with updated doc and his previous revision and it cannot access to other documents. The only field that guaranteed to be unique is document _id. If it's possible and doesn't produce security/privacy issues, use email as doc _id to be ensure that it's unique.

Otherwise you have to create a view with target field as a key and check for it existence first before create a new doc on the client side. However, this logic easily becomes ruined when you'll replicate docs from other instance.

Upvotes: 2

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