Fix typos

lib/dao.js

@@ -40,7 +40,7 @@ function DataAccessObject() {
 
 
 DataAccessObject._forDB = function (data) {
-    if(!this.schema.isRelational()) {
+    if(!(this.schema.isRelational && this.schema.isRelational())) {
         return data;
     }
     var res = {};

lib/datasource.js

@@ -1271,7 +1271,7 @@ DataSource.prototype.defineOperation = function (name, options, fn) {
   this._operations[name] = options;
 }
 
-DataSource.prototype.isRational = function() {
+DataSource.prototype.isRelational = function() {
     return this.adapter && this.adapter.relational;
 }
 

lib/sql.js

@@ -6,7 +6,7 @@ module.exports = BaseSQL;
 function BaseSQL() {
 }
 
-BaseSQL.prototype.rational = true;
+BaseSQL.prototype.relational = true;
 
 BaseSQL.prototype.query = function () {
     throw new Error('query method should be declared in adapter');