Add support for INDEX INCLUDE (#1301)

Author: aidanharan

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## Unreleased
 
+#### Added
+
+- [#1301](https://github.com/rails-sqlserver/activerecord-sqlserver-adapter/pull/1301) Add support for INDEX INCLUDE.
+
 #### Changed
 
 - [#1273](https://github.com/rails-sqlserver/activerecord-sqlserver-adapter/pull/1273) TinyTDS v3+ is now required.

lib/active_record/connection_adapters/sqlserver/schema_creation.rb

@@ -6,6 +6,8 @@ module SQLServer
       class SchemaCreation < SchemaCreation
         private
 
+        delegate :quoted_include_columns_for_index, to: :@conn
+
         def supports_index_using?
           false
         end
@@ -44,11 +46,16 @@ def visit_CreateIndexDefinition(o)
           sql << "INDEX"
           sql << "#{quote_column_name(index.name)} ON #{quote_table_name(index.table)}"
           sql << "(#{quoted_columns(index)})"
+          sql << "INCLUDE (#{quoted_include_columns(index.include)})" if supports_index_include? && index.include
           sql << "WHERE #{index.where}" if index.where
 
           sql.join(" ")
         end
 
+        def quoted_include_columns(o)
+          (String === o) ? o : quoted_include_columns_for_index(o)
+        end
+
         def add_column_options!(sql, options)
           sql << " DEFAULT #{quote_default_expression_for_column_definition(options[:default], options[:column])}" if options_include_default?(options)
           if options[:collation].present?

lib/active_record/connection_adapters/sqlserver/schema_statements.rb

@@ -49,6 +49,7 @@ def indexes(table_name)
               name = index["index_name"]
               unique = index["index_description"].match?(/unique/)
               where = select_value("SELECT [filter_definition] FROM sys.indexes WHERE name = #{quote(name)}", "SCHEMA")
+              include_columns = index_include_columns(table_name, name)
               orders = {}
               columns = []
 
@@ -63,11 +64,31 @@ def indexes(table_name)
                 columns << column
               end
 
-              indexes << IndexDefinition.new(table_name, name, unique, columns, where: where, orders: orders)
+              indexes << IndexDefinition.new(table_name, name, unique, columns, where: where, orders: orders, include: include_columns.presence)
             end
           end
         end
 
+        def index_include_columns(table_name, index_name)
+          sql = <<~SQL
+            SELECT
+                ic.index_id,
+                c.name AS column_name
+            FROM
+                sys.indexes i
+            JOIN
+                sys.index_columns ic ON i.object_id = ic.object_id AND i.index_id = ic.index_id
+            JOIN
+                sys.columns c ON ic.object_id = c.object_id AND ic.column_id = c.column_id
+            WHERE
+                i.object_id = OBJECT_ID('#{table_name}')
+                AND i.name = '#{index_name}'
+                AND ic.is_included_column = 1;
+          SQL
+
+          select_all(sql, "SCHEMA").map { |row| row["column_name"] }
+        end
+
         def columns(table_name)
           return [] if table_name.blank?
 
@@ -421,6 +442,15 @@ def schema_names
           query_values(sql, "SCHEMA")
         end
 
+        def quoted_include_columns_for_index(column_names) # :nodoc:
+          return quote_column_name(column_names) if column_names.is_a?(Symbol)
+
+          quoted_columns = column_names.each_with_object({}) do |name, result|
+            result[name.to_sym] = quote_column_name(name).dup
+          end
+          add_options_for_index_columns(quoted_columns).values.join(", ")
+        end
+
         private
 
         def data_source_sql(name = nil, type: nil)

lib/active_record/connection_adapters/sqlserver_adapter.rb

@@ -143,6 +143,10 @@ def supports_partial_index?
         true
       end
 
+      def supports_index_include?
+        true
+      end
+
       def supports_expression_index?
         false
       end