Merge bc767a0ad3 into a07a19e6d9

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1448 TILs and counting..._
+_1447 TILs and counting..._
 
 ---
 
@@ -986,7 +986,6 @@ _1448 TILs and counting..._
 - [Update Column Versus Update Attribute](rails/update-column-versus-update-attribute.md)
 - [Upgrading Your Manifest For Sprocket's 4](rails/upgrading-your-manifest-for-sprockets-4.md)
 - [Use IRB And Ruby Flags With Rails Console](rails/use-irb-and-ruby-flags-with-rails-console.md)
-- [Validate Column Data With Check Constraints](rails/validate-column-data-with-check-constraints.md)
 - [Verify And Read A Signed Cookie Value](rails/verify-and-read-a-signed-cookie-value.md)
 - [Where Am I In The Partial Iteration?](rails/where-am-i-in-the-partial-iteration.md)
 - [Why Redirect And Return In Controllers](rails/why-redirect-and-return-in-controllers.md)

rails/validate-column-data-with-check-constraints.md

@@ -1,32 +0,0 @@
-# Validate Column Data With Check Constraints
-
-A check constraint is a feature of database systems like PostgreSQL that allows
-you to enforce rules about the data that goes in a table's column. As of Rails
-6.1, ActiveRecord provides a way to add a check constraint via the DSL.
-
-In this example, we want to ensure that the value going into the
-reading_statuses.status column is one of four values. Nothing else besides
-these four values should be allowed.
-
-```ruby
-class AddReadingStatusTable < ActiveRecord::Migration[7.2]
-  def change
-    create_table :reading_statuses do |t|
-      t.references :user, null: false, foreign_key: true
-      t.references :book, null: false, foreign_key: true
-      t.string :status, null: false
-      t.timestamps
-    end
-
-    add_check_constraint
-      :reading_statuses,
-      "status in ('started', 'completed', 'abandoned', 'already_read')",
-      name: "reading_statuses_valid_status_check"
-  end
-end
-```
-
-The `#add_check_constraint` method takes the name of the table and a SQL clause
-that can evaluate to true or false for a given row. We can optionally include
-the name of the check constraint (e.g. {table_name}_{column_name}_check) like
-we've done above.