Should I use DBref?

1 Answer. DBref isn’t anything like a Foreign key in traditional relational systems. Its only a convention which easily tells a driver (who’s capable of) to autoload those referred documents. Basically, I would say that you should only use those DBrefs if the linked document can be of variable type.

What is the use of @DBref?

DBRefs are references from one document to another using the value of the first document’s _id field, collection name, and, optionally, its database name. By including these names, DBRefs allow documents located in multiple collections to be more easily linked with documents from a single collection.

When should I use mysql over MongoDB?

MongoDB uses JavaScript as query language while MySQL uses the Structured Query Language (SQL). MongoDB is an ideal choice if you have unstructured and/or structured data with the potential for rapid growth while MYSQL is a great choice if you have structured data and need a traditional relational database.

Is MongoDB good for transactional database?

Even though it has improved its transactional capabilities over the last few years, MongoDB is still architecturally inferior to modern transactional databases such as YugaByte DB. Using transactions in MongoDB today essentially means giving up on high performance and horizontal scalability.

What field must each MongoDB document have?

_id field
In MongoDB, each document stored in a collection requires a unique _id field that acts as a primary key. If an inserted document omits the _id field, the MongoDB driver automatically generates an ObjectId for the _id field.

Should I use joins in MongoDB?

If we were using a relational database, we could perform a join on users and stores, and get all our objects in a single query. But MongoDB does not support joins and so, at times, requires bit of denormalization.

Should I use MongoDB _ID?

To your questions: Is it ok to use Mongo’s “Object ID” as its unique identifier? Yes, it is intended for this purpose. Making unique IDs can be a pain in sharded environments, so MongoDB does this for you.

Is it safe to use dbref in MongoDB?

Dbref in my opinion should be avoided when work with mongodb, at least if you work with big systems that require scalability. As i know all drivers make additional request to load DBRef, so it’s not ‘join’ within database, it is very expensive.

What is a dbref in SQL Server?

Under the covers, there was no relational magic. A DBRef is just three fields wrapped up to hide the fact that they simply are an $id ObjectId for the document pointed to, a $ref name for the collection that object id is in and, optionally, a $db database name if it is in a different database.

What is the difference between dbrefs and manual references?

Manual referencesare an alternative, and the docs saymanual references are preferable to DBREFs (though I’m not sure why). DBREFs are helpful when the referenced object lives in another database or where the collection name would not otherwise be obvious.

Do dbrefs work anywhere?

DBRefs look great on paper, but experience tells us that they don’t work anywhere as well as the name might suggest. Join us as we look at the feature that no one should use and why. Sometimes a feature just looks too good not to use it. That was the case some years back with MongoDB’s DBRef fields.