Add Rudimentary support for Microsoft SQL Server

See: #306

Author: n-rodriguez

lib/ajax-datatables-rails/datatable/column.rb

@@ -4,18 +4,20 @@ module AjaxDatatablesRails
   module Datatable
     class Column
 
-      TYPE_CAST_DEFAULT = 'VARCHAR'
-      TYPE_CAST_MYSQL   = 'CHAR'
-      TYPE_CAST_SQLITE  = 'TEXT'
-      TYPE_CAST_ORACLE  = 'VARCHAR2(4000)'
+      TYPE_CAST_DEFAULT   = 'VARCHAR'
+      TYPE_CAST_MYSQL     = 'CHAR'
+      TYPE_CAST_SQLITE    = 'TEXT'
+      TYPE_CAST_ORACLE    = 'VARCHAR2(4000)'
+      TYPE_CAST_SQLSERVER = 'VARCHAR(4000)'
 
       DB_ADAPTER_TYPE_CAST = {
         mysql:          TYPE_CAST_MYSQL,
         mysql2:         TYPE_CAST_MYSQL,
         sqlite:         TYPE_CAST_SQLITE,
         sqlite3:        TYPE_CAST_SQLITE,
         oracle:         TYPE_CAST_ORACLE,
-        oracleenhanced: TYPE_CAST_ORACLE
+        oracleenhanced: TYPE_CAST_ORACLE,
+        sqlserver:      TYPE_CAST_SQLSERVER,
       }.freeze
 
       attr_reader :datatable, :index, :options

spec/ajax-datatables-rails/datatable/column_spec.rb

@@ -167,12 +167,12 @@
       expect(column.send(:type_cast)).to eq('VARCHAR')
     end
 
-    it 'returns VARCHAR if :db_adapter is :oracle' do
+    it 'returns VARCHAR2(4000) if :db_adapter is :oracle' do
       allow_any_instance_of(AjaxDatatablesRails::Configuration).to receive(:db_adapter) { :oracle }
       expect(column.send(:type_cast)).to eq('VARCHAR2(4000)')
     end
 
-    it 'returns VARCHAR if :db_adapter is :oracleenhanced' do
+    it 'returns VARCHAR2(4000) if :db_adapter is :oracleenhanced' do
       allow_any_instance_of(AjaxDatatablesRails::Configuration).to receive(:db_adapter) { :oracleenhanced }
       expect(column.send(:type_cast)).to eq('VARCHAR2(4000)')
     end
@@ -196,5 +196,10 @@
       allow_any_instance_of(AjaxDatatablesRails::Configuration).to receive(:db_adapter) { :sqlite3 }
       expect(column.send(:type_cast)).to eq('TEXT')
     end
+
+    it 'returns VARCHAR(4000) if :db_adapter is :sqlserver' do
+      allow_any_instance_of(AjaxDatatablesRails::Configuration).to receive(:db_adapter) { :sqlserver }
+      expect(column.send(:type_cast)).to eq('VARCHAR(4000)')
+    end
   end
 end