Create or Update Sequelize

Question

I'm using Sequelize in my Nodejs project and I found a problem that I'm having a hard time to solve. Basically I have a cron that gets an array of objects from a server than inserts it on my database as a object ( for this case, cartoons ). But if I already have one of the objects, I have to update it.

Basically I have a array of objects and a could use the BulkCreate() method. But as the Cron starts again, it doesn't solve it so I was needing some sort of update with an upsert true flag. And the main issue: I must have a callback that fires just once after all these creates or updates. Does anyone have an idea of how can I do that? Iterate over an array of object.. creating or updating it and then getting a single callback after?

Thanks for the attention

Answer 1

From the docs, you don't need to query where to perform the update once you have the object. Also, the use of promise should simplify callbacks:

Implementation

function upsert(values, condition) {     return Model         .findOne({ where: condition })         .then(function(obj) {             // update             if(obj)                 return obj.update(values);             // insert             return Model.create(values);         }) } 

Usage

upsert({ first_name: 'Taku' }, { id: 1234 }).then(function(result){     res.status(200).send({success: true}); }); 

Note

1. This operation is not atomic.
2. Creates 2 network calls.

which means it is advisable to re-think the approach and probably just update values in one network call and either:

1. Look at the value returned (i.e. rows_affected) and decide what to do.
2. Return success if update operation succeeds. This is because whether the resource exists is not within this service's responsibility.

Answer 2

You can use upsert It's way easier.

Implementation details:

• MySQL - Implemented as a single query INSERT values ON DUPLICATE KEY UPDATE values
• PostgreSQL - Implemented as a temporary function with exception handling: INSERT EXCEPTION WHEN unique_constraint UPDATE
• SQLite - Implemented as two queries INSERT; UPDATE. This means that the update is executed regardless of whether the row already existed or not
• MSSQL - Implemented as a single query using MERGE and WHEN (NOT) MATCHED THEN Note that SQLite returns undefined for created, no matter if the row was created or updated. This is because SQLite always runs INSERT OR IGNORE + UPDATE, in a single query, so there is no way to know whether the row was inserted or not.