Add column and index query methods to ActiveRecord::Schema

[#4219 state:resolved]

Signed-off-by: José Valim <jose.valim@gmail.com>

activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

@@ -582,6 +582,11 @@ def column(column_name, type, options = {})
         @base.add_column(@table_name, column_name, type, options)
       end
 
+      # Checks to see if a column exists. See SchemaStatements#column_exists?
+      def column_exists?(column_name, type = nil, options = nil)
+        @base.column_exists?(@table_name, column_name, type, options)
+      end
+
       # Adds a new index to the table. +column_name+ can be a single Symbol, or
       # an Array of Symbols. See SchemaStatements#add_index
       #
@@ -596,6 +601,11 @@ def index(column_name, options = {})
         @base.add_index(@table_name, column_name, options)
       end
 
+      # Checks to see if an index exists. See SchemaStatements#index_exists?
+      def index_exists?(column_name, options = {})
+        @base.index_exists?(@table_name, column_name, options)
+      end
+
       # Adds timestamps (created_at and updated_at) columns to the table. See SchemaStatements#add_timestamps
       # ===== Example
       #  t.timestamps

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -24,10 +24,59 @@ def table_exists?(table_name)
       # Returns an array of indexes for the given table.
       # def indexes(table_name, name = nil) end
 
+      # Checks to see if an index exists on a table for a given index definition
+      #
+      # === Examples
+      #  # Check an index exists
+      #  index_exists?(:suppliers, :company_id)
+      #
+      #  # Check an index on multiple columns exists
+      #  index_exists?(:suppliers, [:company_id, :company_type])
+      #
+      #  # Check a unique index exists
+      #  index_exists?(:suppliers, :company_id, :unique => true)
+      #
+      #  # Check an index with a custom name exists
+      #  index_exists?(:suppliers, :company_id, :name => "idx_company_id"
+      def index_exists?(table_name, column_name, options = {})
+        column_names = Array.wrap(column_name)
+        index_name = options.key?(:name) ? options[:name].to_s : index_name(table_name, :column => column_names)
+        if options[:unique]
+          indexes(table_name).any?{ |i| i.unique && i.name == index_name }
+        else
+          indexes(table_name).any?{ |i| i.name == index_name }
+        end
+      end
+
       # Returns an array of Column objects for the table specified by +table_name+.
       # See the concrete implementation for details on the expected parameter values.
       def columns(table_name, name = nil) end
 
+      # Checks to see if a column exists in a given table.
+      #
+      # === Examples
+      #  # Check a column exists
+      #  column_exists?(:suppliers, :name)
+      #
+      #  # Check a column exists of a particular type
+      #  column_exists?(:suppliers, :name, :string)
+      #
+      #  # Check a column exists with a specific definition
+      #  column_exists?(:suppliers, :name, :string, :limit => 100)
+      def column_exists?(table_name, column_name, type = nil, options = nil)
+        column_name = column_name.to_s
+        if type
+          if options
+            sql_type = type_to_sql(type, options[:limit], options[:precision], options[:scale])
+            columns(table_name).any?{ |c| c.name == column_name && c.sql_type == sql_type }
+          else
+            columns(table_name).any?{ |c| c.name == column_name && c.type == type }
+          end
+        else
+          columns(table_name).any?{ |c| c.name == column_name }
+        end
+      end
+
       # Creates a new table with the name +table_name+. +table_name+ may either
       # be a String or a Symbol.
       #
@@ -293,7 +342,7 @@ def add_index(table_name, column_name, options = {})
           @logger.warn("Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{index_name_length} characters. Skipping.")
           return
         end
-        if index_exists?(table_name, index_name, false)
+        if index_name_exists?(table_name, index_name, false)
           @logger.warn("Index name '#{index_name}' on table '#{table_name}' already exists. Skipping.")
           return
         end
@@ -314,7 +363,7 @@ def add_index(table_name, column_name, options = {})
       #   remove_index :accounts, :name => :by_branch_party
       def remove_index(table_name, options = {})
         index_name = index_name(table_name, options)
-        unless index_exists?(table_name, index_name, true)
+        unless index_name_exists?(table_name, index_name, true)
           @logger.warn("Index name '#{index_name}' on table '#{table_name}' does not exist. Skipping.")
           return
         end
@@ -351,11 +400,11 @@ def index_name(table_name, options) #:nodoc:
         end
       end
 
-      # Verify the existence of an index.
+      # Verify the existence of an index with a given name.
       #
       # The default argument is returned if the underlying implementation does not define the indexes method,
       # as there's no way to determine the correct answer in that case.
-      def index_exists?(table_name, index_name, default)
+      def index_name_exists?(table_name, index_name, default)
         return default unless respond_to?(:indexes)
         indexes(table_name).detect { |i| i.name == index_name }
       end

activerecord/test/cases/active_schema_test_mysql.rb

@@ -17,8 +17,8 @@ def teardown
   end
 
   def test_add_index
-    # add_index calls index_exists? which can't work since execute is stubbed
-    ActiveRecord::ConnectionAdapters::MysqlAdapter.send(:define_method, :index_exists?) do |*|
+    # add_index calls index_name_exists? which can't work since execute is stubbed
+    ActiveRecord::ConnectionAdapters::MysqlAdapter.send(:define_method, :index_name_exists?) do |*|
       false
     end
     expected = "CREATE  INDEX `index_people_on_last_name` ON `people` (`last_name`)"
@@ -35,7 +35,7 @@ def test_add_index
 
     expected = "CREATE  INDEX `index_people_on_last_name_and_first_name` ON `people` (`last_name`(15), `first_name`(10))"
     assert_equal expected, add_index(:people, [:last_name, :first_name], :length => {:last_name => 15, :first_name => 10})
-    ActiveRecord::ConnectionAdapters::MysqlAdapter.send(:remove_method, :index_exists?)
+    ActiveRecord::ConnectionAdapters::MysqlAdapter.send(:remove_method, :index_name_exists?)
   end
 
   def test_drop_table

activerecord/test/cases/migration_test.rb

@@ -128,9 +128,9 @@ def test_add_index_length_limit
       good_index_name = 'x' * Person.connection.index_name_length
       too_long_index_name = good_index_name + 'x'
       assert_nothing_raised { Person.connection.add_index("people", "first_name", :name => too_long_index_name) }
-      assert !Person.connection.index_exists?("people", too_long_index_name, false)
+      assert !Person.connection.index_name_exists?("people", too_long_index_name, false)
       assert_nothing_raised { Person.connection.add_index("people", "first_name", :name => good_index_name) }
-      assert Person.connection.index_exists?("people", good_index_name, false)
+      assert Person.connection.index_name_exists?("people", good_index_name, false)
     end
 
     def test_remove_nonexistent_index
@@ -146,8 +146,8 @@ def test_rename_index
         Person.connection.add_index('people', [:first_name], :name => 'old_idx')
         assert_nothing_raised { Person.connection.rename_index('people', 'old_idx', 'new_idx') }
         # if the adapter doesn't support the indexes call, pick defaults that let the test pass
-        assert !Person.connection.index_exists?('people', 'old_idx', false)
-        assert Person.connection.index_exists?('people', 'new_idx', true)
+        assert !Person.connection.index_name_exists?('people', 'old_idx', false)
+        assert Person.connection.index_name_exists?('people', 'new_idx', true)
       end
     end
 
@@ -158,6 +158,53 @@ def test_double_add_index
       end
     end
 
+    def test_index_exists
+      Person.connection.create_table :testings do |t|
+        t.column :foo, :string, :limit => 100
+        t.column :bar, :string, :limit => 100
+      end
+      Person.connection.add_index :testings, :foo
+
+      assert Person.connection.index_exists?(:testings, :foo)
+      assert !Person.connection.index_exists?(:testings, :bar)
+    ensure
+      Person.connection.drop_table :testings rescue nil
+    end
+
+    def test_index_exists_on_multiple_columns
+      Person.connection.create_table :testings do |t|
+        t.column :foo, :string, :limit => 100
+        t.column :bar, :string, :limit => 100
+      end
+      Person.connection.add_index :testings, [:foo, :bar]
+
+      assert Person.connection.index_exists?(:testings, [:foo, :bar])
+    ensure
+      Person.connection.drop_table :testings rescue nil
+    end
+
+    def test_unique_index_exists
+      Person.connection.create_table :testings do |t|
+        t.column :foo, :string, :limit => 100
+      end
+      Person.connection.add_index :testings, :foo, :unique => true
+
+      assert Person.connection.index_exists?(:testings, :foo, :unique => true)
+    ensure
+      Person.connection.drop_table :testings rescue nil
+    end
+
+    def test_named_index_exists
+      Person.connection.create_table :testings do |t|
+        t.column :foo, :string, :limit => 100
+      end
+      Person.connection.add_index :testings, :foo, :name => "custom_index_name"
+
+      assert Person.connection.index_exists?(:testings, :foo, :name => "custom_index_name")
+    ensure
+      Person.connection.drop_table :testings rescue nil
+    end
+
     def testing_table_with_only_foo_attribute
       Person.connection.create_table :testings, :id => false do |t|
         t.column :foo, :string
@@ -974,6 +1021,45 @@ def test_change_column_default_to_null
       assert_nil Person.new.first_name
     end
 
+    def test_column_exists
+      Person.connection.create_table :testings do |t|
+        t.column :foo, :string
+      end
+
+      assert Person.connection.column_exists?(:testings, :foo)
+      assert !Person.connection.column_exists?(:testings, :bar)
+    ensure
+      Person.connection.drop_table :testings rescue nil
+    end
+
+    def test_column_exists_with_type
+      Person.connection.create_table :testings do |t|
+        t.column :foo, :string
+        t.column :bar, :decimal, :precision => 8, :scale => 2
+      end
+
+      assert Person.connection.column_exists?(:testings, :foo, :string)
+      assert !Person.connection.column_exists?(:testings, :foo, :integer)
+      assert Person.connection.column_exists?(:testings, :bar, :decimal)
+      assert !Person.connection.column_exists?(:testings, :bar, :integer)
+    ensure
+      Person.connection.drop_table :testings rescue nil
+    end
+
+    def test_column_exists_with_definition
+      Person.connection.create_table :testings do |t|
+        t.column :foo, :string, :limit => 100
+        t.column :bar, :decimal, :precision => 8, :scale => 2
+      end
+
+      assert Person.connection.column_exists?(:testings, :foo, :string, :limit => 100)
+      assert !Person.connection.column_exists?(:testings, :foo, :string, :limit => 50)
+      assert Person.connection.column_exists?(:testings, :bar, :decimal, :precision => 8, :scale => 2)
+      assert !Person.connection.column_exists?(:testings, :bar, :decimal, :precision => 10, :scale => 2)
+    ensure
+      Person.connection.drop_table :testings rescue nil
+    end
+
     def test_add_table
       assert !Reminder.table_exists?
 
@@ -1684,6 +1770,20 @@ def test_index_creates_index_with_options
       end
     end
 
+    def test_index_exists
+      with_change_table do |t|
+        @connection.expects(:index_exists?).with(:delete_me, :bar, {})
+        t.index_exists?(:bar)
+      end
+    end
+
+    def test_index_exists_with_options
+      with_change_table do |t|
+        @connection.expects(:index_exists?).with(:delete_me, :bar, {:unique => true})
+        t.index_exists?(:bar, :unique => true)
+      end
+    end
+
     def test_change_changes_column
       with_change_table do |t|
         @connection.expects(:change_column).with(:delete_me, :bar, :string, {})