Added customer composite key

db/migrate/20250218071800_modify_customers_table.rb

@@ -0,0 +1,97 @@
+class ModifyCustomersTable < ActiveRecord::Migration[7.1]
+  def up
+    # First, remove the foreign key constraint from reservations
+    remove_foreign_key :reservations, :customers if foreign_key_exists?(:reservations, :customers)
+    
+    # Create temporary columns without constraints
+    add_column :customers, :first_name, :string unless column_exists?(:customers, :first_name)
+    add_column :customers, :surname, :string unless column_exists?(:customers, :surname)
+    add_column :customers, :original_phone, :string unless column_exists?(:customers, :original_phone)
+    
+    # Copy data
+    execute <<-SQL
+      UPDATE customers 
+      SET first_name = name,
+          surname = '',
+          original_phone = phone
+    SQL
+    
+    # Now add the NOT NULL constraints
+    change_column_null :customers, :surname, false
+    change_column_null :customers, :original_phone, false
+    
+    # Remove old name column
+    remove_column :customers, :name if column_exists?(:customers, :name)
+    
+    # Remove existing indexes
+    remove_index :customers, name: :index_customers_composite_with_company, if_exists: true
+    remove_index :customers, name: :index_customers_on_name_and_company_id, if_exists: true
+    remove_index :customers, name: :index_customers_on_company_id, if_exists: true
+    remove_index :customers, name: :index_customers_on_composite_key, if_exists: true
+    remove_index :customers, name: :index_customers_on_composite_key_and_company, if_exists: true
+    
+    # Create new indexes
+    add_index :customers, [:first_name, :surname, :original_phone], 
+              unique: true,
+              name: 'index_customers_on_composite_key'
+    
+    add_index :customers, [:first_name, :surname, :original_phone, :company_id], 
+              unique: true,
+              name: 'index_customers_on_composite_key_and_company'
+              
+    # Add a non-unique index on company_id for performance
+    add_index :customers, :company_id, 
+              name: 'index_customers_on_company_id'
+              
+    # Add new columns to reservations
+    add_column :reservations, :customer_first_name, :string
+    add_column :reservations, :customer_surname, :string
+    add_column :reservations, :customer_original_phone, :string
+    
+    # Update reservations data
+    execute <<-SQL
+      UPDATE reservations 
+      SET customer_first_name = (SELECT first_name FROM customers WHERE customers.id = reservations.customer_id),
+          customer_surname = (SELECT surname FROM customers WHERE customers.id = reservations.customer_id),
+          customer_original_phone = (SELECT original_phone FROM customers WHERE customers.id = reservations.customer_id)
+    SQL
+    
+    # Add foreign key constraint
+    add_foreign_key :reservations, :customers, 
+                    primary_key: [:first_name, :surname, :original_phone],
+                    column: [:customer_first_name, :customer_surname, :customer_original_phone]
+                    
+    # Remove old columns
+    remove_column :customers, :id if column_exists?(:customers, :id)
+    remove_column :reservations, :customer_id if column_exists?(:reservations, :customer_id)
+  end
+
+  def down
+    # Add back the id columns
+    add_column :customers, :id, :primary_key
+    add_column :reservations, :customer_id, :integer
+    
+    # Remove the composite foreign key
+    remove_foreign_key :reservations, :customers if foreign_key_exists?(:reservations, :customers)
+    remove_column :reservations, :customer_first_name
+    remove_column :reservations, :customer_surname
+    remove_column :reservations, :customer_original_phone
+    
+    # Add back the original foreign key
+    add_foreign_key :reservations, :customers
+    
+    # Drop composite indexes safely
+    execute <<-SQL
+      DROP INDEX IF EXISTS index_customers_on_composite_key;
+      DROP INDEX IF EXISTS index_customers_on_composite_key_and_company;
+    SQL
+    
+    # Restore the original columns
+    add_column :customers, :name, :string
+    execute "UPDATE customers SET name = first_name"
+    
+    remove_column :customers, :first_name
+    remove_column :customers, :surname
+    remove_column :customers, :original_phone
+  end
+end