Fix matching view's real column name (rails-sqlserver#1133)

Author: aidanharan

CHANGELOG.md

@@ -1,3 +1,9 @@
+## Unreleased
+
+#### Fixed
+
+- [#1133](https://github.com/rails-sqlserver/activerecord-sqlserver-adapter/pull/1133) Fix matching view's real column name
+
 ## v7.0.5.0
 
 #### Fixed

lib/active_record/connection_adapters/sqlserver/schema_statements.rb

@@ -601,17 +601,19 @@ def view_information(table_name)
             identifier = SQLServer::Utils.extract_identifiers(table_name)
             information_query_table = identifier.database.present? ? "[#{identifier.database}].[INFORMATION_SCHEMA].[VIEWS]" :  "[INFORMATION_SCHEMA].[VIEWS]"
             view_info = select_one "SELECT * FROM #{information_query_table} WITH (NOLOCK) WHERE TABLE_NAME = #{quote(identifier.object)}", "SCHEMA"
+
             if view_info
               view_info = view_info.with_indifferent_access
               if view_info[:VIEW_DEFINITION].blank? || view_info[:VIEW_DEFINITION].length == 4000
                 view_info[:VIEW_DEFINITION] = begin
-                  select_values("EXEC sp_helptext #{identifier.object_quoted}", "SCHEMA").join
+                                                select_values("EXEC sp_helptext #{identifier.object_quoted}", "SCHEMA").join
                                               rescue
                                                 warn "No view definition found, possible permissions problem.\nPlease run GRANT VIEW DEFINITION TO your_user;"
                                                 nil
-                end
+                                              end
               end
             end
+
             view_info
           end
         end
@@ -620,7 +622,8 @@ def views_real_column_name(table_name, column_name)
           view_definition = view_information(table_name)[:VIEW_DEFINITION]
           return column_name unless view_definition
 
-          match_data = view_definition.match(/CREATE\s+VIEW.*AS\s+SELECT.*\W([\w-]*)\s+AS\s+#{column_name}/im)
+          # Remove "CREATE VIEW ... AS SELECT ..." and then match the column name.
+          match_data = view_definition.sub(/CREATE\s+VIEW.*AS\s+SELECT\s/, '').match(/([\w-]*)\s+AS\s+#{column_name}\W/im)
           match_data ? match_data[1] : column_name
         end
 

test/cases/view_test_sqlserver.rb

@@ -9,18 +9,20 @@ class ViewTestSQLServer < ActiveRecord::TestCase
     before do
       connection.drop_table :view_casing_table rescue nil
       connection.create_table :view_casing_table, force: true do |t|
-        t.boolean :Default_Falsey, null: false, default: false
-        t.boolean :Default_Truthy, null: false, default: true
-        t.string  :default_string, null: false, default: "abc"
+        t.boolean :Default_Falsey,      null: false, default: false
+        t.boolean :Default_Truthy,      null: false, default: true
+        t.string  :default_string_null, null: true,  default: nil
+        t.string  :default_string,      null: false, default: "abc"
       end
 
       connection.execute("DROP VIEW IF EXISTS view_casing_table_view;")
       connection.execute <<-SQL
         CREATE VIEW view_casing_table_view AS
               SELECT id AS id,
-                     default_falsey AS falsey,
-                     default_truthy AS truthy,
-                     default_string AS s
+                     default_falsey      AS falsey,
+                     default_truthy      AS truthy,
+                     default_string_null AS s_null,
+                     default_string      AS s
               FROM view_casing_table
       SQL
     end
@@ -34,12 +36,14 @@ class ViewTestSQLServer < ActiveRecord::TestCase
       assert_equal false, obj.falsey
       assert_equal true, obj.truthy
       assert_equal "abc", obj.s
+      assert_nil   obj.s_null
       assert_equal 0, klass.count
 
       obj.save!
       assert_equal false, obj.falsey
       assert_equal true, obj.truthy
       assert_equal "abc", obj.s
+      assert_nil   obj.s_null
       assert_equal 1, klass.count
     end
   end