Programming Ecto

Writing Queries with Schemas

When we looked at queries in the last chapter, we deliberately chose to write them without schemas. This is still a good choice in some circumstances, but schemas provide some helpful shortcuts and we promised that we’d revisit them later. Now’s the time. In this section, we’ll start writing queries that work with schemas, and we’ll also consider when it’s best not to.

Converting a Schema-less Query

Let’s look at a query we ran in the last chapter:

priv/examples/schema_02.exs

artist_id = "1"
q = from "artists", where: [id: type(^artist_id, :integer)],
  select: [:name]
Repo.all(q)
#=> [%{name: "Miles Davis"}]

As you may recall, artist_id is initialized as a string, ...