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Subash
Subash

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Rails - annotate method

#rails #annotate

The annotate method

is used to add an SQL comment to queries generated from the relation. Here is an example

Bullet.includes(:user). find_by_id(params[:id])
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The above query uses include to eager-load the user table. We can use annotate to add a sql comment to explain the same like

Bullet.includes(:user). annotate('Eager loading user table'). find_by_id(params[:id])
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That's it.

Now when you see the rails server logs, you can find the sql comment which was added in the query explanation.

Processing by BulletsController#show as HTML Parameters: {"id"=>"5"} Bullet Load (0.1ms) SELECT "bullets".* FROM "bullets" WHERE "bullets"."id" = ? /* Eager loading user table */ LIMIT ? [["id", 5], ["LIMIT", 1]] ↳ app/controllers/bullets_controller.rb:73:in `set_bullet' User Load (0.1ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? [["id", 2]]
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Caution: Some escaping is performed, however untrusted user input should not be used.

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