check if object has own property in "var in" loop

lib/dialects/mysql/query-generator.js

@@ -15,13 +15,15 @@ module.exports = (function() {
         , attrStr = []
 
       for (var attr in attributes) {
-        var dataType = attributes[attr]
-
-        if (Utils._.includes(dataType, 'PRIMARY KEY')) {
-          primaryKeys.push(attr)
-          attrStr.push(Utils.addTicks(attr) + " " + dataType.replace(/PRIMARY KEY/, ''))
-        } else {
-          attrStr.push(Utils.addTicks(attr) + " " + dataType)
+        if (attributes.hasOwnProperty(attr)) {
+          var dataType = attributes[attr]
+
+          if (Utils._.includes(dataType, 'PRIMARY KEY')) {
+            primaryKeys.push(attr)
+            attrStr.push(Utils.addTicks(attr) + " " + dataType.replace(/PRIMARY KEY/, ''))
+          } else {
+            attrStr.push(Utils.addTicks(attr) + " " + dataType)
+          }
         }
       }
 
@@ -380,10 +382,12 @@ module.exports = (function() {
       var fields = []
 
       for (var name in factory.attributes) {
-        var definition = factory.attributes[name]
+        if (factory.attributes.hasOwnProperty(name)) {
+          var definition = factory.attributes[name]
 
-        if (definition && (definition.indexOf('auto_increment') > -1)) {
-          fields.push(name)
+          if (definition && (definition.indexOf('auto_increment') > -1)) {
+            fields.push(name)
+          }
         }
       }