Use ActiveRecord's attributes_for_update hook to avoid identity inserts.

I found a better way! cc @annaswims

Author: metaskills

CHANGELOG.md

@@ -42,9 +42,10 @@
   * edition
 * Removed tests for old issue #164. Handled by core types now.
 * The `activity_stats` method. Please put this in a gem if needed.
-* We no longger use regular expressions to fix identity inserts. Use ActiveRecord or public ID insert helper.
+* We no longer use regular expressions to fix identity inserts. Use ActiveRecord or public ID insert helper.
 * All auto reconnect and SQL retry logic. Got too complicated and stood in the way of AR's pool. Speed boost too.
 * The adapter will no longer try to remove duplicate order by clauses. Use relation `reorder`, `unscope`, etc.
+* We no longer use regular expressions to remove identity columns from updates. Now with `attributes_for_update` AR hook.
 
 #### Fixed
 

lib/active_record/connection_adapters/sqlserver/core_ext/attribute_methods.rb

@@ -0,0 +1,25 @@
+require 'active_record/attribute_methods'
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLServer
+      module CoreExt
+        module AttributeMethods
+
+
+          private
+
+          def attributes_for_update(attribute_names)
+            super.reject do |name|
+              column = self.class.columns_hash[name]
+              column && column.respond_to?(:is_identity?) && column.is_identity?
+            end
+          end
+
+        end
+      end
+    end
+  end
+end
+
+ActiveRecord::Base.send :include, ActiveRecord::ConnectionAdapters::SQLServer::CoreExt::AttributeMethods

lib/active_record/connection_adapters/sqlserver/database_statements.rb

@@ -16,12 +16,7 @@ def execute(sql, name = nil)
         end
 
         def exec_query(sql, name = 'SQL', binds = [], sqlserver_options = {})
-          if update_sql?(sql)
-            sql = strip_ident_from_update(sql)
-            sp_executesql(sql, name, binds)
-          else
-            sp_executesql(sql, name, binds)
-          end
+          sp_executesql(sql, name, binds)
         end
 
         def exec_insert(sql, name, binds, _pk = nil, _sequence_name = nil)

lib/active_record/connection_adapters/sqlserver/schema_statements.rb

@@ -411,26 +411,6 @@ def insert_sql?(sql)
           !(sql =~ /^\s*(INSERT|EXEC sp_executesql N'INSERT)/i).nil?
         end
 
-        def strip_ident_from_update(sql)
-          # We can't update Identiy columns in sqlserver.  So, strip out the id from the update.
-          # There has to be a better way to handle this, but this'll do for now.
-          table_name = get_table_name(sql)
-          id_column = identity_column(table_name)
-          if id_column
-            regex_col_name = Regexp.quote(quote_column_name(id_column.name))
-            if sql =~ /, #{regex_col_name} = @?[0-9]*/
-              sql = sql.gsub(/, #{regex_col_name} = @?[0-9]*/, '')
-            elsif sql =~ /\s#{regex_col_name} = @?[0-9]*,/
-              sql = sql.gsub(/\s#{regex_col_name} = @?[0-9]*,/, '')
-            end
-          end
-          sql
-        end
-
-        def update_sql?(sql)
-          !(sql =~ /^\s*(UPDATE|EXEC sp_executesql N'UPDATE)/i).nil?
-        end
-
         def identity_column(table_name)
           schema_cache.columns(table_name).find(&:is_identity?)
         end

lib/active_record/connection_adapters/sqlserver_adapter.rb

@@ -6,6 +6,7 @@
 require 'active_record/connection_adapters/sqlserver/core_ext/explain'
 require 'active_record/connection_adapters/sqlserver/core_ext/explain_subscriber'
 require 'active_record/connection_adapters/sqlserver/core_ext/relation'
+require 'active_record/connection_adapters/sqlserver/core_ext/attribute_methods'
 require 'active_record/connection_adapters/sqlserver/version'
 require 'active_record/connection_adapters/sqlserver/type'
 require 'active_record/connection_adapters/sqlserver/database_limits'