Database service - what is acquire method for?

[ThePlenkov]

Hi!

I've started a new database service inheriting from cds.Database service. Currently my get requests get failed here:

  async begin() {
    const tx = this.context ? this : this.tx()
    tx. = await tx.acquire(tx.context)
    try {
      await tx.send('BEGIN')
    } catch (e) {
      tx.release(tx.dbc)
      throw e
    }
    return tx
  }

so what happens - the default class logic is like this - in case if context is provided ( like Read Entity ) then it tries to call acquire method of itself. There are several issues:

• there is no default acquire method implementation. I see that Hana and SQlite classes have this method declared directly there
• for TS experience I propose to define this method also in the parent class even as an abstract one. It's not yet clear also - what should be returned from this method too

Thanks!

[ThePlenkov]

@schwma do you know who can help? Thanks

[schwma]

@patricebender @BobdenOs @SamuelBrucksch could you please take a look?

[BobdenOs]

@ThePlenkov cds.DatabaseService is the old database service. You should inherit from the pluggable database service which can be found here

If your target database uses SQL you can inherit from the SQLService directly. Which can be found here.

[ThePlenkov]

Thanks for the reply. The principal difference - is that community project doesn't have typescript yet. So it's hard to use it without definitions. So my idea was to create another class similar to cds-dbs/DatabaseService. However the initital question was about acquire - it looks like this method shouldn't be used by redefining begin method in a common class.

[BobdenOs]

The new database service doesn't redefine begin. It inherits from cds.Service not from cds.DatabaseService. It explicitly defines begin so that all depending classes have a structured API to implement. By inheriting from the pluggable db service. It is only needed to define a factory and the set function. As is hinted at by the error message 2b overriden in subclass.

As for typescript definitions of the db-service package. The whole API is still in beta and for some parts there are already jsdoc definitions provided, but not yet for everything.