methods for getting auto increment fields

lib/dialects/mysql/query-generator.js

@@ -277,6 +277,15 @@ module.exports = (function() {
       })
 
       return result
+    },
+
+    findAutoIncrementField: function(factory) {
+      var fields = Utils._.map(factory.attributes, function(definition, name) {
+        var isAutoIncrementField = (definition && (definition.indexOf('auto_increment') > -1))
+        return isAutoIncrementField ? name : null
+      })
+
+      return Utils._.compact(fields)
     }
   }
 

lib/dialects/sqlite/query-generator.js

@@ -55,6 +55,15 @@ module.exports = (function() {
       })
 
       return result
+    },
+
+    findAutoIncrementField: function(factory) {
+      var fields = Utils._.map(factory.attributes, function(definition, name) {
+        var isAutoIncrementField = (definition && (definition.indexOf('INTEGER PRIMARY KEY') == 0))
+        return isAutoIncrementField ? name : null
+      })
+
+      return Utils._.compact(fields)
     }
   }