diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 828e46637de5debf11ecdcb13ac12ea53bd43f20..53cc52f200f6f16dd84681a02e4384426a7bb4a8 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -1,4 +1,5 @@
 require 'active_record/connection_adapters/abstract_adapter'
+require 'active_record/connection_adapters/mysql/column'
 require 'active_record/connection_adapters/mysql/schema_creation'
 require 'active_record/connection_adapters/mysql/schema_definitions'
 require 'active_record/connection_adapters/mysql/schema_dumper'
@@ -19,51 +20,6 @@ def schema_creation
         MySQL::SchemaCreation.new(self)
       end
 
-      class Column < ConnectionAdapters::Column # :nodoc:
-        delegate :strict, :extra, to: :sql_type_metadata, allow_nil: true
-
-        def initialize(*)
-          super
-          assert_valid_default(default)
-          extract_default
-        end
-
-        def extract_default
-          if blob_or_text_column?
-            @default = null || strict ? nil : ''
-          end
-        end
-
-        def has_default?
-          return false if blob_or_text_column? # MySQL forbids defaults on blob and text columns
-          super
-        end
-
-        def blob_or_text_column?
-          /\A(?:tiny|medium|long)?blob\b/ === sql_type || type == :text
-        end
-
-        def unsigned?
-          /\bunsigned\z/ === sql_type
-        end
-
-        def case_sensitive?
-          collation && !collation.match(/_ci$/)
-        end
-
-        def auto_increment?
-          extra == 'auto_increment'
-        end
-
-        private
-
-        def assert_valid_default(default)
-          if blob_or_text_column? && default.present?
-            raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
-          end
-        end
-      end
-
       class MysqlTypeMetadata < DelegateClass(SqlTypeMetadata) # :nodoc:
         attr_reader :extra, :strict
 
@@ -234,7 +190,7 @@ def each_hash(result) # :nodoc:
       end
 
       def new_column(field, default, sql_type_metadata = nil, null = true, default_function = nil, collation = nil) # :nodoc:
-        Column.new(field, default, sql_type_metadata, null, default_function, collation)
+        MySQL::Column.new(field, default, sql_type_metadata, null, default_function, collation)
       end
 
       # Must return the MySQL error number from the exception, if the exception has an
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/column.rb b/activerecord/lib/active_record/connection_adapters/mysql/column.rb
new file mode 100644
index 0000000000000000000000000000000000000000..9c45fdd44a8e447b154221d3b0c0d3d8140c5bca
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/column.rb
@@ -0,0 +1,50 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      class Column < ConnectionAdapters::Column # :nodoc:
+        delegate :strict, :extra, to: :sql_type_metadata, allow_nil: true
+
+        def initialize(*)
+          super
+          assert_valid_default
+          extract_default
+        end
+
+        def has_default?
+          return false if blob_or_text_column? # MySQL forbids defaults on blob and text columns
+          super
+        end
+
+        def blob_or_text_column?
+          /\A(?:tiny|medium|long)?blob\b/ === sql_type || type == :text
+        end
+
+        def unsigned?
+          /\bunsigned\z/ === sql_type
+        end
+
+        def case_sensitive?
+          collation && collation !~ /_ci\z/
+        end
+
+        def auto_increment?
+          extra == 'auto_increment'
+        end
+
+        private
+
+        def extract_default
+          if blob_or_text_column?
+            @default = null || strict ? nil : ''
+          end
+        end
+
+        def assert_valid_default
+          if blob_or_text_column? && default.present?
+            raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/column_definition_test.rb b/activerecord/test/cases/column_definition_test.rb
index 783a374116f6342acb656fe48dbfee3b66f27298..dc05aad19e75b7450108f9a52ef5610dad019bd8 100644
--- a/activerecord/test/cases/column_definition_test.rb
+++ b/activerecord/test/cases/column_definition_test.rb
@@ -41,49 +41,49 @@ def test_should_specify_not_null_if_null_option_is_false
       if current_adapter?(:Mysql2Adapter)
         def test_should_set_default_for_mysql_binary_data_types
           type = SqlTypeMetadata.new(type: :binary, sql_type: "binary(1)")
-          binary_column = AbstractMysqlAdapter::Column.new("title", "a", type)
+          binary_column = MySQL::Column.new("title", "a", type)
           assert_equal "a", binary_column.default
 
           type = SqlTypeMetadata.new(type: :binary, sql_type: "varbinary")
-          varbinary_column = AbstractMysqlAdapter::Column.new("title", "a", type)
+          varbinary_column = MySQL::Column.new("title", "a", type)
           assert_equal "a", varbinary_column.default
         end
 
         def test_should_be_empty_string_default_for_mysql_binary_data_types
           type = SqlTypeMetadata.new(type: :binary, sql_type: "binary(1)")
-          binary_column = AbstractMysqlAdapter::Column.new("title", "", type, false)
+          binary_column = MySQL::Column.new("title", "", type, false)
           assert_equal "", binary_column.default
 
           type = SqlTypeMetadata.new(type: :binary, sql_type: "varbinary")
-          varbinary_column = AbstractMysqlAdapter::Column.new("title", "", type, false)
+          varbinary_column = MySQL::Column.new("title", "", type, false)
           assert_equal "", varbinary_column.default
         end
 
         def test_should_not_set_default_for_blob_and_text_data_types
           assert_raise ArgumentError do
-            AbstractMysqlAdapter::Column.new("title", "a", SqlTypeMetadata.new(sql_type: "blob"))
+            MySQL::Column.new("title", "a", SqlTypeMetadata.new(sql_type: "blob"))
           end
 
           text_type = AbstractMysqlAdapter::MysqlTypeMetadata.new(
             SqlTypeMetadata.new(type: :text))
           assert_raise ArgumentError do
-            AbstractMysqlAdapter::Column.new("title", "Hello", text_type)
+            MySQL::Column.new("title", "Hello", text_type)
           end
 
-          text_column = AbstractMysqlAdapter::Column.new("title", nil, text_type)
+          text_column = MySQL::Column.new("title", nil, text_type)
           assert_equal nil, text_column.default
 
-          not_null_text_column = AbstractMysqlAdapter::Column.new("title", nil, text_type, false)
+          not_null_text_column = MySQL::Column.new("title", nil, text_type, false)
           assert_equal "", not_null_text_column.default
         end
 
         def test_has_default_should_return_false_for_blob_and_text_data_types
           binary_type = SqlTypeMetadata.new(sql_type: "blob")
-          blob_column = AbstractMysqlAdapter::Column.new("title", nil, binary_type)
+          blob_column = MySQL::Column.new("title", nil, binary_type)
           assert !blob_column.has_default?
 
           text_type = SqlTypeMetadata.new(type: :text)
-          text_column = AbstractMysqlAdapter::Column.new("title", nil, text_type)
+          text_column = MySQL::Column.new("title", nil, text_type)
           assert !text_column.has_default?
         end
       end