Loopback 4, querying with SQLQuery with postgres connector

[vishalvisd]

Description/Steps to reproduce

This is how I have defined my repository following very generic example given at loopback documentation:-

import {DefaultCrudRepository, juggler} from '@loopback/repository';
import {AModel} from '../models';
import {TimeseriesDataSource} from '../datasources';
import {inject} from '@loopback/core';

export class AModelRepository extends DefaultCrudRepository<
  AModel,
  typeof AModel.prototype.id
> {
  constructor(
    @inject('datasources.timeseries') dataSource: TimeseriesDataSource,
  ) {
    super(AModel, dataSource);
  }
}

I was hoping that if do AModelRepository.execute(sql, null, cb) it would work. But its giving error - Error: Not implemented

Any help is highly appreciated.

[simblechris]

I'm getting the same issue using MySQL

From what I saw in a different issue this might be an issue mapping from the new crud repository in LB4 to legacy-juggler-bridge

[dhmlau]

Seems like it's not implemented. https://github.com/strongloop/loopback-next/blob/master/packages/repository/src/repositories/legacy-juggler-bridge.ts#L381-L389

[shendkardevesh]

You can use and this worked for me.

this.dataSource.execute("select * from tbl_player", [])

[gregra81]

@shendkardevesh Can you please share more context? Maybe share a bigger chunk of your code. If you use this.dataSource in your repository, I'm assuming this relates to juggler.DataSource. But it does not have an execute method

[bajtos]

Datasource-level execute method was added by loopbackio/loopback-datasource-juggler#1671.

Related issues:

• Connecting to graph databases #2053
• repository execute method gives an 'not implement' error #2189

[gregra81]

@bajtos This is great. When do you think it will be available in the lb4 official release?

[samarpanB]

I created a base repository class extending the DefaulCrudRepository and added an implementation for execute function which actually uses the datasource execute function to perform the task. Then, we used this new class as base repository class. This was a workaround until execute is implemented at repository level.
Here is the implementation

export abstract class AppDefaultCrudRepository<
  T extends Entity,
  ID
> extends DefaultCrudRepository<T, ID> {
  constructor(
    entityClass: typeof Entity & {
      prototype: T;
    },
    dataSource: MyDataSource,
  ) {
    super(entityClass, dataSource);
  }
  execute(
    command: Command,
    parameters: NamedParameters | PositionalParameters,
    options?: Options,
  ): Promise<AnyObject> {
    // Commented below statement until it is implemented 
    // return super.execute(command, parameters, options);
    return this.dataSource.execute(command, parameters, options);
  }
}

@bajtos do you think it is worthwhile to add this to DefaulCrudRepository itself until it is implemented ? That ways, developers can use it with no breaking change in future.

[bajtos]

@samarpanB

do you think it is worthwhile to add this to DefaulCrudRepository

Yes please!

@gregra81

When do you think it will be available in the lb4 official release?

We are intentionally leaving this issue open because it's a great opportunity for new contributors. You are welcome to contribute the changes yourself, we are happy to help you along the way.

[samarpanB]

Okay @bajtos. I’ll generate a PR for this soon. Thanks.