Last Sync: 2022-08-11 12:00:04

Databases/MongoDB/Create_collections_and_documents_with_Mongoose.md

@@ -6,3 +6,105 @@ tags:
 ---
 
 # Create collections and documents with Mongoose
+
+## Connecting to our database with Mongoose
+Now that we have installed and configured MongoDB, we need to connect to it via Node.js. Mongoose is a simple API for interacting with a Mongo database via Node.
+
+With Mongoose installed we can connect to a database. We don't have any Mongo databases yet beyond the defaults but the following Mongoose connection logic will create and connect to a new database called `playground`:
+
+Providing the Mongo server is running (execture `mongod`), we will see the confirmation message in the console. 
+
+```js
+mongoose
+  .connect("mongodb://127.0.0.1/playground")
+  .then(() => console.log("Connected to MongoDB"))
+  .catch((err) => console.error(err));
+```
+
+## Collections and documents
+In order start adding collections and documents to our database, we use Mongoose's schema structure. This is specific to Mongoose and is not a structure that is a part of Mongo in general.
+
+We use a schema to define the shape of documents in a MongoDB collection. To do this we instantiate an instance of the Mongoose `Schema` class and set our properties:
+
+### Creating a schema
+
+```js
+const courseSchema = new mongoose.Schema({
+  name: String,
+  author: String,
+  tags: [String],
+  data: {type: Date, default: Date.now}, // if unspecified, entry will default to current date
+  isPublished: Boolean
+});
+
+```
+This is just like defining an inteface or type within TypeScript.
+#### Available data types
+
+The following data types are available:
+* `String`
+* `Number`
+* `Boolean`
+* `Array`
+* `Date`
+* `Buffer`
+* `ObjectID` (for UUIDs)
+
+### Models
+
+Once we have established our schema we can then create a **model** of it. A model is basically a class representation of the interface we define in the schema:
+
+```js
+const Course = mongoose.model("Course", courseSchema);
+```
+With this in place, we can then create instances of the model. This stands in relation to the model as an object does to a class:
+
+```js
+const course = new Course({
+  name: "Node.js Course",
+  author: "Ozzy Osbourne",
+  tags: ["node", "backend"],
+  isPublished: true 
+});
+```
+![](/img/mongoose-hierarchy.svg)
+
+Having created a database, connected to it with Mongoose, and created a model we will see our collection reflected in Compass:
+
+![](img/../../../img/mongo-collection.png)
+
+### Adding a document
+We have our database (`playground`) and collection (`courses`) established. We now need to add documents to our collection. We will move our previous code into a function since this will be an asynchronous process:
+
+```js
+const nodeCourse = new Course({
+  name: "Python Course",
+  author: "Terry Ogleton",
+  tags: ["python"],
+  isPublished: true,
+});
+
+async function addCourseDocToDb(courseDocument) {
+  const result = await courseDocument.save();
+  console.log(result);
+}
+
+addCourseDocToDb(nodeCourse);
+```
+
+When we run this, we call the `save` method on the Mongoose schema.  We will then have the Mongo document outputted to the console:
+```
+{
+  name: 'Python Course',
+  author: 'Terry Ogleton',
+  tags: [ 'python' ],
+  isPublished: true,
+  _id: new ObjectId("62f4ac989d2fec2f01596b9b"),
+  date: 2022-08-11T07:15:36.978Z,
+  __v: 0
+}
+```
+
+This will also be reflected in Compass:
+
+![](/img/mongo-doc-added.png)

Databases/MongoDB/Create_database.md

@@ -26,7 +26,7 @@ _Compass_ is a graphical interface for viewing and interacting with the data in
 
 ![](/img/mongo-compass.png)
 
-## Arch Linux troublshooting
+## Arch Linux troubleshooting
 Most times any problems will be a result of a Mongo process that is already running. Resolve with:
 
 ```bash