added toSql on the node-sql instances

lib/dao-factory.js

@@ -68,7 +68,11 @@ module.exports = (function() {
       ;(function(methodName) {
       ;(function(methodName) {
         DAOFactory.prototype[methodName] = function() {
         DAOFactory.prototype[methodName] = function() {
           var dataset = this.dataset()
           var dataset = this.dataset()
-          return dataset[methodName].apply(dataset, arguments)
+            , result  = dataset[methodName].apply(dataset, arguments)
+
+          result.toSql = function(){ return result.toQuery().text }
+
+          return result
         }
         }
       })(methodName)
       })(methodName)
     }
     }

spec/dao-factory.spec.js

@@ -2498,5 +2498,27 @@ describe(Helpers.getTestDialectTeaser("DAOFactory"), function() {
         expect(query1.text).toEqual(query2.text)
         expect(query1.text).toEqual(query2.text)
       })
       })
     })
     })
+
+    describe("toSql", function() {
+      it("transforms the node-sql instance into a proper sql string", function() {
+        var sql    = this.User.select("username").toSql()
+        var sqlMap = {
+          postgres: 'SELECT username FROM "users"',
+          mysql:    'SELECT `username` FROM `users`',
+          sqlite:   'SELECT username FROM "users"'
+        }
+        expect(sql).toEqual(sqlMap[dialect])
+      })
+
+      it("transforms node-sql instances with chaining into a proper sql string", function() {
+        var sql    = this.User.select("username").select("firstName").group("username").toSql()
+        var sqlMap = {
+          postgres: 'SELECT username, firstName FROM "users" GROUP BY username',
+          mysql:    'SELECT `username`, `firstName` FROM `users` GROUP BY username',
+          sqlite:   'SELECT username, firstName FROM "users" GROUP BY username'
+        }
+        expect(sql).toEqual(sqlMap[dialect])
+      })
+    })
   })
   })
 })
 })