Attaching models to data sources

Models are connected to backend systems via data sources that use data source connectors. You use the model APIs to interact with the model and the data source to which it is attached.

Best practice is to first add data sources to your app, as explained in Defining data sources. Then, create models and attach them to the data sources as desired.

When you create a new model with the model generator, you specify which data source to attach it to from among those you’ve added to the application and the default db data source (that uses the memory connector).

For example:

$ lb model
? Enter the model name: myModel
? Select the data-source to attach myModel to: mysql (mysql)
? Select model's base class: PersistedModel
? Expose myModel via the REST API? Yes
? Custom plural form (used to build REST URL):
Let's add some myModel properties now.
...

Or with API Connect:

$ apic create --type model
? Enter the model name: myModel
? Select the data-source to attach myModel to: mongoDS (mongodb)
? Select model's base class: PersistedModel
? Expose myModel via the REST API? Yes
? Custom plural form (used to build REST URL):
Let's add some test2 properties now.
...

When prompted for the data source to attach to, select a data source that you created previously or the default db data source that uses the in-memory connector. 

? Enter the model name: myModel
? Select the data-source to attach myModel to:
  db (memory)
❯ mongoDS (mongodb)
  (no data-source)

To change the data source a model uses after you’ve created the model, edit the application’s server/model-config.json and set the dataSource property for the model. For example, to make myModel use the corp1 data source:

"myModel": {
    "dataSource": "corp1",
    "public": true
  }

By default, the model generator attaches models to the db (in-memory) data source.