How to insert/update multiple records in single call to create/update_attributes in Rhomobile

Question

As per the performance tip in Rhom API of Rhomobile,

We should prepare the whole data set first and then call the create/update_attributes for better performance over preparing single record then calling create inside loop.

As per my knowledge, create method takes the object of single record as like this,

@account = Account.create(
  {"name" => "some new record", "industry" => "electronics"}
)

So i wonder how to create/update multiple records on a single call?

Thanks in advance.

Answer 1

First, I have no idea how much this will actually affect performance, whether positively or negatively, and have never measured it.

That said, you can wrap all the CRUD calls in a transaction, to minimise the DB connections opened and closed. This can also help you with maintaining referential integrity, by rolling back changes if some record is causing a problem with your new dataset.

# Load all DB Models, to ensure they are available before first time import
Rho::RHO.load_all_sources();

# Get instance of DB to work transactions with
db = ::Rho::RHO.get_db_partitions()['local'] # Get reference to model db
db.start_transaction()  # BEGIN transaction

... Do all your create/update/deletes

if (was_import_successful)
  db.commit   # COMMIT transaction
else
  db.rollback() # ROLLBACK transaction
end

Answer 2

Using Rhom, you can still write SQL queries for the underlying SQLite engine. But you need to understand what is the Table format you're using.

The default PropertyBags data model are all stored in a key value store in a single Table, if you're looking for the maximum performance, you better switch to FixedSchema data models. In this case you loose some flexibility but you gain some performance and you save same space.

My suggestion is to use transactions, like you're already doing, switch to FixedSchema data models and see if you're fine in that way. If you really need to increase the speed, maybe you can achieve what you want in a different way, something like importing a SQLite database created on the server side.

This is the method that RhoConnect uses for the bulk synchronization.