Azure Cosmos DB: Build a Node.js app using JavaScript SDK to manage Azure Cosmos DB SQL API data

• 09/24/2018
• 8 minutes to read
• Contributors
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Azure Cosmos DB is Microsoft’s globally distributed multi-model database service. You can quickly create and query document, key/value, and graph databases, all of which benefit from the global distribution and horizontal scale capabilities at the core of Azure Cosmos DB.

This quickstart demonstrates how to create an Azure Cosmos DB SQL API account, document database, and container using the Azure portal. You then build and run a console app built on the SQL JavaScript SDK. This quickstart uses version 2.0 of the JavaScript SDK.

Prerequisites

If you don't have an Azure subscription, create a free account before you begin.

You can Try Azure Cosmos DB for free without an Azure subscription, free of charge and commitments. Or, you can use the Azure Cosmos DB Emulator with a URI of https://localhost:8081. The Primary Key is provided in Authenticating requests.

• In addition:
  • Node.js version v6.0.0 or higher
  • Git

Create a database account

1. In a new browser window, sign in to the Azure portal.

2. Click Create a resource > Databases > Azure Cosmos DB.

   

3. In the New account page, enter the settings for the new Azure Cosmos DB account.

   Setting	Value	Description
   ID	Enter a unique name	Enter a unique name to identify this Azure Cosmos DB account. Because documents.azure.com is appended to the ID that you provide to create your URI, use a unique but identifiable ID. The ID can contain only lowercase letters, numbers, and the hyphen (-) character, and it must contain 3 to 50 characters.
   API	SQL	The API determines the type of account to create. Azure Cosmos DB provides five APIs: SQL (document database), Gremlin (graph database), MongoDB (document database), Azure Table, and Cassandra. Each API currently requires you to create a separate account. Select SQL because in this quickstart you are creating a document database that is queryable using SQL syntax and accessible with the SQL API. Learn more about the SQL API
   Subscription	Your subscription	Select Azure subscription that you want to use for this Azure Cosmos DB account.
   Resource Group	Create new Then enter the same unique name as provided above in ID	Select Create New, then enter a new resource-group name for your account. For simplicity, you can use the same name as your ID.
   Location	Select the region closest to your users	Select geographic location in which to host your Azure Cosmos DB account. Use the location that's closest to your users to give them the fastest access to the data.
   Enable geo-redundancy	Leave blank	This creates a replicated version of your database in a second (paired) region. Leave this blank.
   Pin to dashboard	Select	Select this box so that your new database account is added to your portal dashboard for easy access.

   Then click Create.

   

4. The account creation takes a few minutes. Wait for the portal to display the Congratulations! Your Azure Cosmos DB account was created page.

   

Add a collection

You can now use the Data Explorer tool in the Azure portal to create a database and collection.

1. Click Data Explorer > New Collection.

   The Add Collection area is displayed on the far right, you may need to scroll right to see it.

   

2. In the Add collection page, enter the settings for the new collection.

   Setting	Suggested value	Description
   Database id	Tasks	Enter Tasks as the name for the new database. Database names must contain from 1 through 255 characters, and they cannot contain /, \, #, ?, or a trailing space.
   Collection id	Items	Enter Items as the name for your new collection. Collection ids have the same character requirements as database names.
   Storage capacity	Fixed (10 GB)	Use the default value of Fixed (10 GB). This value is the storage capacity of the database.
   Throughput	400 RU	Change the throughput to 400 request units per second (RU/s). Storage capacity must be set to Fixed (10 GB) in order to set throughput to 400 RU/s. If you want to reduce latency, you can scale up the throughput later.

   In addition to the preceding settings, you can optionally add Unique keys for the collection. Let's leave the field empty in this example. Unique keys provide developers with the ability to add a layer of data integrity to the database. By creating a unique key policy while creating a collection, you ensure the uniqueness of one or more values per partition key. To learn more, refer to the Unique keys in Azure Cosmos DB article.

   Click OK.

   Data Explorer displays the new database and collection.

   

Add sample data

You can now add data to your new collection using Data Explorer.

1. In Data Explorer, the new database appears in the Collections pane. Expand the Tasks database, expand the Items collection, click Documents, and then click New Documents.

   

2. Now add a document to the collection with the following structure.

   {
       "id": "1",
       "category": "personal",
       "name": "groceries",
       "description": "Pick up apples and strawberries.",
       "isComplete": false
   }
   

3. Once you've added the json to the Documents tab, click Save.

   

4. Create and save one more document where you insert a unique value for the id property, and change the other properties as you see fit. Your new documents can have any structure you want as Azure Cosmos DB doesn't impose any schema on your data.

Query your data

You can now use queries in Data Explorer to retrieve and filter your data.

1. See that by default, the query is set to SELECT * FROM c. This default query retrieves and displays all documents in the collection.

   

2. Stay on the Documents tab, and change the query by clicking the Edit Filter button, adding ORDER BY c._ts DESC to the query predicate box, and then clicking Apply Filter.

   

This modified query lists the documents in descending order based on their time stamp, so now your second document is listed first. If you're familiar with SQL syntax, you can enter any of the supported SQL queries in this box.

That completes our work in Data Explorer. Before we move on to working with code, note that you can also use Data Explorer to create stored procedures, UDFs, and triggers to perform server-side business logic as well as scale throughput. Data Explorer exposes all of the built-in programmatic data access available in the APIs, but provides easy access to your data in the Azure portal.

Clone the sample application

Now let's clone a SQL API app from Github, set the connection string, and run it.

1. Open a command prompt, create a new folder named git-samples, then close the command prompt.

   md "C:\git-samples"
   

2. Open a git terminal window, such as git bash, and use the cd command to change to the new folder to install the sample app.

   cd "C:\git-samples"
   

3. Run the following command to clone the sample repository. This command creates a copy of the sample app on your computer.

   git clone https://github.com/Azure-Samples/azure-cosmos-db-sql-api-nodejs-getting-started.git
   

Review the code

This step is optional. If you're interested in learning how the database resources are created in the code, you can review the following snippets. Otherwise, you can skip ahead to Update your connection string.

Note, if you are familiar with the previous version of the JavaScript SDK, you may be used to seeing the terms 'collection' and 'document.' Because Azure Cosmos DB supports multiple API models, version 2.0+ of the JavaScript SDK uses the generic terms 'container', which may be a collection, graph, or table and 'item' to describe the content of the container.

The following snippets are all taken from the app.js file.

• The CosmosClient is initialized.

  const client = new CosmosClient({ endpoint: endpoint, auth: { masterKey: masterKey } });
  

• A new database is created.

  const { database } = await client.databases.createIfNotExists({ id: databaseId });
  

• A new container (collection) is created.

  const { container } = await client.database(databaseId).containers.createIfNotExists({ id: containerId });
  

• An item (document) is created.

  const { item } = await client.database(databaseId).container(containerId).items.create(itemBody);
  

• A SQL query over JSON is performed.

  const querySpec = {
      query: "SELECT VALUE r.children FROM root r WHERE r.lastName = @lastName",
      parameters: [
          {
              name: "@lastName",
              value: "Andersen"
          }
      ]
  };
  
  const { result: results } = await client.database(databaseId).container(containerId).items.query(querySpec).toArray();
  for (var queryResult of results) {
      let resultString = JSON.stringify(queryResult);
      console.log(`\tQuery returned ${resultString}\n`);
  }
  

Update your connection string

Now go back to the Azure portal to get your connection string information and copy it into the app.

1. In the Azure portal, in your Azure Cosmos DB account, in the left navigation click Keys, and then click Read-write Keys. You'll use the copy buttons on the right side of the screen to copy the URI and Primary Key into the config.js file in the next step.

   

2. In Open the config.js file.

3. Copy your URI value from the portal (using the copy button) and make it the value of the endpoint key in config.js.

   config.endpoint = "https://FILLME.documents.azure.com"

4. Then copy your PRIMARY KEY value from the portal and make it the value of the config.primaryKey in config.js. You've now updated your app with all the info it needs to communicate with Azure Cosmos DB.

   config.primaryKey = "FILLME"

Run the app

1. Run npm install in a terminal to install required npm modules

2. Run node app.js in a terminal to start your node application.

You can now go back to Data Explorer and see query, modify, and work with this new data.

Review SLAs in the Azure portal

The throughput, storage, availability, latency, and consistency of the resources in your account are monitored in the Azure portal. Let's take a quick look at these metrics.

1. Click Metrics in the navigation menu.

   

2. Click through each of the tabs so you're aware of the metrics Azure Cosmos DB provides.

   Each chart that's associated with the Azure Cosmos DB Service Level Agreements (SLAs) provides a line that shows if any of the SLAs have been violated. Azure Cosmos DB makes monitoring your SLAs transparent with this suite of metrics.

   

Clean up resources

If you're not going to continue to use this app, delete all resources created by this quickstart with the following steps so you don't incur any charges:

1. In the Azure portal, select Resource groups on the far left, and then select the resource group you created.

   If the left menu is collapsed, click to expand it.

   

2. In the new window select the resource group, and then click Delete resource group.

   

3. In the new window, type the name of the resource group to delete, and then click Delete.

Next steps

In this quickstart, you've learned how to create an Azure Cosmos DB account, create a collection using the Data Explorer, and run an app. You can now import additional data to your Cosmos DB account.