phoenix ecto preload
To preload associations in Elixir Phoenix Ecto, you can use the
preload function. The
preload function is used to load associated data along with the main query, reducing the number of database queries required.
preload, you first need to define the associations in your Ecto schema using the
has_one macros. Once the associations are defined, you can use the
preload function in your queries to load the associated data.
Here's an example of how to use
preload in Elixir Phoenix Ecto:
# Define the associations in your schema
defmodule MyApp.User do
schema "users" do
has_many :posts, MyApp.Post
defmodule MyApp.Post do
schema "posts" do
belongs_to :user, MyApp.User
# Preload the associated data in your query
query = from u in MyApp.User,
result = MyApp.Repo.all(query)
In the example above, we define a one-to-many association between
Post schemas. We use the
has_many macro in the
User schema and the
belongs_to macro in the
Post schema to define the association.
To preload the associated
posts when querying for
users, we include
preload: [:posts] in the query. This tells Ecto to load the associated posts along with the users in a single query.
Finally, we execute the query using
MyApp.Repo.all(query) to retrieve the results.
preload, you can efficiently load associated data in Elixir Phoenix Ecto, reducing the number of database queries and improving performance.