faq.jade

extends layout

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  style.
    hr {
      display: block;
      margin: 30px 0;
    }

block content
  h2 FAQ
  :markdown
    **Q**. Why don't my changes to arrays get saved when I update an element directly?
  :js
    doc.array[3] = 'changed';
    doc.save();
  :markdown
    **A**. Mongoose doesn't create getters/setters for array indexes; without them mongoose never gets notified of the change and so doesn't know to persist the new value. The work-around is to use [MongooseArray#set]() available in **Mongoose >= 3.2.0**.
  :js
    // 3.2.0
    doc.array.set(3, 'changed');
    doc.save();

    // if running a version less than 3.2.0, you must mark the array modified before saving.
    doc.array[3] = 'changed';
    doc.markModified('array');
    doc.save();
  hr
  :markdown
    **Q**. Why doesn't mongoose allow me to directly assign schemas to paths?
  :js
    var userSchema = new Schema({ name: String });
    new Schema({ user: userSchema })
  :markdown
    **A**. Schemas have a one-to-one mapping with documents. Documents have `save` and `remove` methods along with their own `pre` and `post` hooks which would lead to code like the following:
  :js
    doc.user.save();  // ?
    doc.user.remove();// ?
    doc.save()
  :markdown
    We've felt that this api would be more confusing than helpful. The counter argument is that arrays of sub-documents already have this functionality, but at best this too leads to confusion (calling `save` on a sub-document is a no-op and exists only to support `pre` save hooks). In the future this is likely to be revisited.
  hr
  :markdown
    **Q**. How can I enable debugging?

    **A**. Set the `debug` option to `true`:
  :js
    mongoose.set('debug', true)
  :markdown
    All executed collection methods will log output of their arguments to your console.
  hr
  :markdown
    **Q**. My `save()` callback never executes. What am I doing wrong?

    **A**. All `collection` actions (insert, remove, queries, etc) are queued until the `connection` opens. It is likely that an error occurred while attempting to connect. Try adding an error handler to your connection.
  :js
    // if connecting on the default mongoose connection
    mongoose.connect(..);
    mongoose.connection.on('error', handleError);

    // if connecting on a separate connection
    var conn = mongoose.createConnection(..);
    conn.on('error', handleError);

  hr
  :markdown
    **Something to add?**

    If you'd like to contribute to this page, please [visit it](https://github.com/learnboost/mongoose/tree/master/docs/faq.jade) on github and use the [Edit](https://github.com/blog/844-forking-with-the-edit-button) button to send a pull request.
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