diff --git a/lib/datastore.js b/lib/datastore.js
index e32e4f3..7141648 100644
--- a/lib/datastore.js
+++ b/lib/datastore.js
@@ -152,14 +152,26 @@ Datastore.prototype.findOne = function (query, callback) {
 
 /**
  * Persist the whole database
+ * @param {Array} data Optional data to persist. If not set, we use the database data
  * @param {Function} cb Optional callback, signature: err
  */
-Datastore.prototype.persistWholeDatabase = function (cb) {
-  var callback = cb || function () {}
+Datastore.prototype.persistWholeDatabase = function (data, cb) {
+  var callback
     , self = this
     , newContents = '';
 
-  self.data.forEach(function (d) {
+  if (!data) {
+    data = self.data;
+  }
+
+  if (typeof data === 'function') {
+    cb = data;
+    data = self.data;
+  }
+
+  callback = cb || function () {};
+
+  data.forEach(function (d) {
     newContents += JSON.stringify(d) + '\n';
   });
 
@@ -167,6 +179,18 @@ Datastore.prototype.persistWholeDatabase = function (cb) {
 };
 
 
+/**
+ * Update the first doc matching query
+ * @param {Object} query
+ * @param {Object} newDoc Will replace the former doc
+ * @param {Function} cb Optional callback, signature: err, replaced?, newDoc
+ */
+Datastore.prototype.updateOne = function (query, newDoc, cb) {
+  var callback = cb || function () {};
+
+};
+
+
 
 
 var d = new Datastore('workspace/test.db');
@@ -174,7 +198,6 @@ d.loadDatabase(function (err) {
   console.log(d.data);
   d.data = [{ff: 'mec'}, {ee: 'test'}];
 
-  d.persistWholeDatabase();
 
 });