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48 lines
1.2 KiB
Markdown
48 lines
1.2 KiB
Markdown
# Create A Custom Named References Column
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The `t.references` and `add_reference` methods both create a foreign key column
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name based on the target table.
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For instance,
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```ruby
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add_reference :guests, :user, foreign_key: true, index: true, null: false
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```
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would create a `user_id` column on the `guests` table.
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At times, you'll need to customize the name of the foreign key column. The
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Rails migration DSL supports this with the `foreign_key` option.
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Here is an example that shows the syntax for both a new table and an existing
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table.
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```ruby
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class AddInvitedByColumnToUser < ActiveRecord::Migration[6.1]
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def change
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create_table :guests, id: :uuid do |t|
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t.string :email, null: false
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t.timestamps
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t.references :invited_by,
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type: :uuid,
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index: true,
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null: false,
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foreign_key: { to_table: :users }
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end
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add_reference :guests, :signed_up_as,
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type: :uuid,
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index: true,
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null: false,
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foreign_key: { to_table: :users }
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end
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end
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```
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The `t.references` call creates a foreign key column to the `users` table named
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`invited_by`. The `add_reference` call adds a `signed_up_as` foreign key column
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to `guests` that points to users.
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[source](https://stackoverflow.com/a/42056089/535590)
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