Trouble understanding eager loading

Question

I've tried to apply eager loading per Craft's docs, but it doesn't seem to work. When I do this, will I have access to all the entry fields? If not, do I have to include all the fields I want in the with attribute?

{% for entry in craft.entries.section('news').with['image'] %}
  {% set image = entry.image[0] ?? null %}
  {% if image %}
    <img src="{{ image.url }}">
  {% endif %}
  {{ entry.title }}
{% endfor %}

When I tried it, the code barfed when trying to output {{ entry.title }}.

Answer 1

there is no .with() method for the ElementCriteriaModel nor is it supported by craft.entries as a chainable method, meaning that it can't be chained to craft.entries query like that:

{% for entry in craft.entries.section('news').with['image'] %}

Especially as an array (hint: you were probably intending to use .with(['image']) instead of .with['image'].

The correct syntax for eager loading elements is:

{% set entries = craft.entries({
    section: 'news',
    with: ['image']
}) %}

or in your case it can be:

{% for entry in craft.entries({ section: 'news', with:['image'] }) %}
  {% set image = entry.image[0] ?? null %}
  {% if image %}
    <img src="{{ image.url }}">
  {% endif %}
  {{ entry.title }}
{% endfor %}

I remember also being frustrated by eager loading in craft (for some reason I also had problems using it at first), but then it turned to be quite useful. It's especially powerful if you'd like to show more then one image per entry, e.g.:

{% for i in entry.image %}
    <img src="{{ i.url }}" alt="">
{% endfor %}

Take care

Answer 2

The original answer is good, but as noted, somewhat incorrect, at least concerning a chainable .with() method.

Here's my attempt to explain things: Speed up your Craft CMS Templates with Eager Loading