Polymorphism

Subtopics

EdgeQL Tutorial

Polymorphism

The [is Type] construct can also be used on any expression to filter out all the objects that don't correspond to the specified type (we've already seen it used with backlinks). Additionally, since the resulting expression is guaranteed to be of the specified type, the type-specific links and properties can now be accessed on it. Try it out with the base type Object or Content and narrow it down to Show (we've only got one Show in this tutorial 🙂):

Input

Run

select Object[is Show] {
  title,
  num_seasons
};

select Object[is Show] {
  title,
  num_seasons
};

Output Objects

Press the 'Run' button to evaluate the input

Input

Run

# This will cause an error since not all Content has num_seasons,
# only Show has that property. Can you fix the query?
select Content {
  title,
  num_seasons
};

# This will cause an error since not all Content has num_seasons,
# only Show has that property. Can you fix the query?
select Content {
  title,
  num_seasons
};

Output Objects

Press the 'Run' button to evaluate the input

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