Quickstart: Use Node.js to connect and query data from Azure Cosmos DB SQL API account

  • 8 minutes to read

This quickstart demonstrates how to use a Node.js app to connect to the SQL API account in Azure Cosmos DB. You can then use Azure Cosmos DB SQL queries to query and manage data. The Node.js app you build in this article uses 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. For the key to use with the emulator, see Authenticating requests.

  • In addition:

Create a database

  1. Go to the Azure portal to create an Azure Cosmos DB account. Search for and select Azure Cosmos DB.

    The Azure portal Databases pane

  2. Select Add.

  3. On the Create Azure Cosmos DB Account page, enter the basic settings for the new Azure Cosmos account.

    Setting Value Description
    Subscription Subscription name Select the Azure subscription that you want to use for this Azure Cosmos account.
    Resource Group Resource group name Select a resource group, or select Create new, then enter a unique name for the new resource group.
    Account Name A unique name Enter a name to identify your Azure Cosmos account. Because documents.azure.com is appended to the name that you provide to create your URI, use a unique name.

    The name can only contain lowercase letters, numbers, and the hyphen (-) character. It must be between 3-31 characters in length.
    API The type of account to create Select Core (SQL) to create a document database and query by using SQL syntax.

    The API determines the type of account to create. Azure Cosmos DB provides five APIs: Core (SQL) and MongoDB for document data, Gremlin for graph data, Azure Table, and Cassandra. Currently, you must create a separate account for each API.

    Learn more about the SQL API.
    Location The region closest to your users Select a geographic location to host your Azure Cosmos DB account. Use the location that is closest to your users to give them the fastest access to the data.

    The new account page for Azure Cosmos DB

  4. Select Review + create. You can skip the Network and Tags sections.

  5. Review the account settings, and then select Create. It takes a few minutes to create the account. Wait for the portal page to display Your deployment is complete.

    The Azure portal Notifications pane

  6. Select Go to resource to go to the Azure Cosmos DB account page.

    The Azure Cosmos DB account page

Add a container

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

  1. Select Data Explorer > New Container.

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

    The Azure portal Data Explorer, Add Container pane

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

    Setting Suggested value Description
    Database ID Tasks Enter ToDoList as the name for the new database. Database names must contain from 1 through 255 characters, and they cannot contain /, \\, #, ?, or a trailing space. Check the Provision database throughput option, it allows you to share the throughput provisioned to the database across all the containers within the database. This option also helps with cost savings.
    Throughput 400 Leave the throughput at 400 request units per second (RU/s). If you want to reduce latency, you can scale up the throughput later.
    Container ID Items Enter Items as the name for your new container. Container IDs have the same character requirements as database names.
    Partition key /category The sample described in this article uses /category as the partition key.

    In addition to the preceding settings, you can optionally add Unique keys for the container. 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 container, 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.

    Select OK. The Data Explorer displays the new database and container.

Add sample data

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

  1. From the Data Explorer, expand the Tasks database, expand the Items container. Select Items, and then select New Item.

    Create new documents in Data Explorer in the Azure portal

  2. Now add a document to the container 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, select Save.

    Copy in json data and select Save in Data Explorer in the Azure portal

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

  1. At the top of the Documents tab in Data Explorer, review the default query SELECT * FROM c. This query retrieves and displays all documents in the collection in ID order.

    Default query in Data Explorer is SELECT * FROM c

  2. To change the query, select Edit Filter, replace the default query with ORDER BY c._ts DESC, and then select Apply Filter.

    Change the default query by adding ORDER BY c._ts DESC and clicking Apply Filter

    The modified query displays the documents in descending order based on their time stamp, so now your second document is listed first.

    Changed query to ORDER BY c._ts DESC and clicking Apply Filter

If you're familiar with SQL syntax, you can enter any supported SQL queries in the query predicate box. You can also use Data Explorer to create stored procedures, UDFs, and triggers for server-side business logic.

Data Explorer provides easy Azure portal access to all of the built-in programmatic data access features available in the APIs. You also use the portal to scale throughput, get keys and connection strings, and review metrics and SLAs for your Azure Cosmos DB account.

Clone the sample application

Now let's clone a Node.js 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 Azure Cosmos 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 object is initialized.

    const client = new CosmosClient({ endpoint, key });

  • Create a new Azure Cosmos database.

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

  • A new container (collection) is created within the database.

    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 on the family database. The query returns all the children of the "Anderson" family.

        const querySpec = {
  	query: 'SELECT VALUE r.children FROM root r WHERE r.lastName = @lastName',
  	parameters: [
  	  {
  		name: '@lastName',
  		value: 'Andersen'
  	  }
  	]
    }

    const { resources: results } = await client
  	.database(databaseId)
  	.container(containerId)
  	.items.query(querySpec)
  	.fetchAll()
    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 the connection string details of your Azure Cosmos account. Copy the connection string into the app so that it can connect to your database.

  1. In the Azure portal, in your Azure Cosmos 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.

    View and copy an access key in the Azure portal, Keys blade

  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 = "<Your Azure Cosmos account URI>"

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

    config.key = "<Your Azure Cosmos account key>"

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, modify, and work with this new data.

Review SLAs in the Azure portal

The Azure portal monitors your Cosmos DB account throughput, storage, availability, latency, and consistency. Charts for metrics associated with an Azure Cosmos DB Service Level Agreement (SLA) show the SLA value compared to actual performance. This suite of metrics makes monitoring your SLAs transparent.

To review metrics and SLAs:

  1. Select Metrics in your Cosmos DB account's navigation menu.

  2. Select a tab such as Latency, and select a timeframe on the right. Compare the Actual and SLA lines on the charts.

    Azure Cosmos DB metrics suite

  3. Review the metrics on the other tabs.

Clean up resources

When you're done with your web app and Azure Cosmos DB account, you can delete the Azure resources you created so you don't incur more charges. To delete the resources:

  1. In the Azure portal, select Resource groups on the far left. If the left menu is collapsed, select Expand button to expand it.

  2. Select the resource group you created for this quickstart.

    Select the resource group to delete

  3. In the new window, select Delete resource group.

    Delete the resource group

  4. In the next window, enter the name of the resource group to delete, and then select Delete.

Next steps

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

Import data into Azure Cosmos DB