Last Sync: 2022-08-13 11:00:04

Databases/MongoDB/Update_document.md

@@ -13,7 +13,9 @@ There are two methods for updating a document
 * update first
 
 ## Query first document update
-With this approach we first execute a [query](/Databases/MongoDB/Querying_a_collection.md) to retrieve the document we want to edit and then make the change. We use the `findById` method to identify the document by its UUID and then `set` to update specified properties on the document.  
+With this approach we first execute a [query](/Databases/MongoDB/Querying_a_collection.md) to retrieve the document we want to edit and then make the change. We use the `findById` method to identify the document by its UUID and then `set` to update specified properties on the document. The `set` method is one of many operators that can be used to update values. For example there is also built-in operators for increment, renaming, multiplying values. 
+
+Query first is best used when you want to secure the update with some prior logic or to validate. For example you may not want to update a course if it is listed as published. You could use a query to determine the publish status and then only update the entry if it returns `isPublished: false`.
 
 ```js
 async function updateCourseFromQuery(id) {
@@ -31,5 +33,38 @@ async function updateCourseFromQuery(id) {
     const result = course.save()
     console.log(result);
 }
-
 ```
+
+## Update first document update
+With this approach we don't bother with a prior query. We are confident that the update is legitimate and do not need to first determine that certain conditions are met. 
+
+To do this we directly use the `update` method, not `find`:
+
+```js
+async function updateCourseFromQuery(id) {
+    const result = await Course.update({_id: id});
+    $set: { // Invoke the set operator 
+        author: 'Terry Nutile'
+        isPublished: true 
+    }
+    console.log(result)
+}
+```
+
+This function will just return some metadata about the update. It won't by default return the updated value. To do this use the `findByIdAndUpdate()` method instead of `update`:
+
+```js
+async function updateCourseFromQuery(id) {
+    const course = await Course.findByIdAndUpdate(id, {
+    $set: { // Invoke the set operator 
+        author: 'Terry Nutile'
+        isPublished: true 
+    }, {new: true}});
+    console.log(result)
+}
+```
+If we don't add `{new: true}`, it will return the document before the update. 
+
+### Updating multiple documents at once
+
+// TODO : Add notes on this