Mongoose - Queries with OR and AND

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Mongoose - Queries with OR and AND

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I'm trying to make a query in mongoose and I can not think of how to put it together. In SQL it would be something like this:

SELECT * FROM MATERIAS 
WHERE
     activo = true AND 
     nivel = $nivel_id AND
    (alldisc = true OR disciplina = $disciplina_id)

where $nivel_id and $disciplina_id variables.

This same thing I'm writing in nodejs and mongoose and I can not think of a good way to do it.

What I have done so far is:

function getMateriasFilter(req, res) {
    var query = Materia.find({'active': true});

    if (req.query.nivel)        query.where('nivel', req.query.nivel);
    if (req.query.disciplina)   query.where('disciplina', req.query.disciplina).or('alldisc', true);

    query
        .populate('nivel')
        .populate('periodo')
        .populate('disciplina')
        .exec(function(err, result) {
            if (err) res.send(err);
            res.json(result); 
        });
}

The line with the discipline ifif complicates me. That condition would be that if the discipline filter exists, I have to bring the one that matches the discipline or those that have the alldisc field in true.

Thank you very much already.

nodejs mongoose

asked by Ezequiel Cohort 21.02.2017 в 06:41

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1 answer

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score 0 · Accepted Answer

I recommend always work in layers , delegate specific functionalities to each one so that you have a single responsibility. Remember that a highly coupled / cohesive application means a very low probability that you can scale and maintain in the future.

The next class acts as repository for a collection. Its function is simply to consult the database.

Tip: preferably tends to use Promesas instead of callbacks because it provides clean syntax in complex processes (avoiding the callback hell ) and In addition, you will benefit if you decide to use the recently approved specification async/await that will appear in ES2017 .

class MateriaRepository {
  filter (nivel disciplina) {
    let where = { active: true };

    if (nivel) {
      where.nivel = nivel;
    }

    if (disciplina) {
      where.$or = [
        {
          alldisc: true
        },
        {
          disciplina
        }
      ]
    }

    return (
      Materia
        .find(where)
        .populate('nivel')
        .populate('periodo')
        .populate('disciplina')
        .exec()
    );
  }
}

This way you can use these methods anywhere.

function getMateriasFilter (req, res) {
  let repository = new MateriaRepository();
  let { nivel, disciplina } = req.query;

  repository
    .filter(nivel, disciplina)
    .then((materias) => (
      res.jsonp(materias)
    ));
}

The previous query is explained as follows:

By default, where only specifies that only active subjects are selected ( active: true ).

If the nivel parameter is available, add an entry to where so that only active subjects are selected and have the specified level.

If the discipline parameter is available, an entry of type $or is added to where to select active , of a certain level and of a certain discipline or if the subject has alldisc: true .