适配器

The BaseModel class DOES NOT interact with the query builders directly. Instead, it relies on the Model adapter class to construct the query builder instances for different database operation.

This separation allows you swap the adapter with your custom implementation to cover advanced use cases.

Creating a custom adapter

Every custom adapter must adhere to the AdapterContract interface.

import { AdapterContract } from '@ioc:Adonis/Lucid/Orm'
class MyAdapter implements AdapterContract {}

You can assign the adapter to the model as follows:

class User extends BaseModel {
  public static $adapter = new MyAdapter()
}

Methods/Properties

Following is the list of methods/properties that every adapter must have.

modelConstructorClient

Returns the query client for a given model constructor.

import { AdapterContract, ModelAdapterOptions } from '@ioc:Adonis/Lucid/Orm'

class MyAdapter implements AdapterContract {
  public modelConstructorClient(model: typeof BaseModel, options?: ModelAdapterOptions) {
    const connection = options?.connection || model.connection
    return connection ? Database.connection(connection) : Database.connection()
  }
}

modelClient

Returns the query client for a given model instance. The default implementation resolves the client as follows

• Return the transaction client if the model has $trx property defined
• Return the query client for a given connection if model instance has $options.connection property defined.
• Finally, look for the connection property on the model constructor (aka static connection property).

import { AdapterContract } from '@ioc:Adonis/Lucid/Orm'

class MyAdapter implements AdapterContract {
  public modelClient(instance: BaseModel) {
  }
}

query

Return the query builder instance for a given Model constructor. The Model.query method internals calls the query method on the adapter.

import { AdapterContract, ModelAdapterOptions } from '@ioc:Adonis/Lucid/Orm'

class MyAdapter implements AdapterContract {
  public query(model: typeof BaseModel, options?: ModelAdapterOptions) {
    return Database.modelQuery(model)
  }
}

insert

Perform the insert operation for a given model instance. The method receives the model instance and an object of attributes to insert.

import { AdapterContract } from '@ioc:Adonis/Lucid/Orm'

class MyAdapter implements AdapterContract {
  public async insert(instance: BaseModel, attributes: any) {
  }
}

update

Perform the update operation for a given model instance. The method receives the model instance and an object of attributes to update.

import { AdapterContract } from '@ioc:Adonis/Lucid/Orm'

class MyAdapter implements AdapterContract {
  public async update(instance: BaseModel, dirtyAttributes: any) {
  }
}

delete

Perform the delete operation for a given model instance. The method receives only the model instance.

import { AdapterContract } from '@ioc:Adonis/Lucid/Orm'

class MyAdapter implements AdapterContract {
  public async delete(instance: BaseModel) {
  }
}

refresh

Refresh the model instance by performing a select query and hydrating its attributes. The method receives only the model instance.

import { AdapterContract } from '@ioc:Adonis/Lucid/Orm'

class MyAdapter implements AdapterContract {
  public async refresh(instance: BaseModel) {
  }
}