Connecting to Cosmos DB
Rest API (SQL API)
To obtain the connection string needed to connect to a Cosmos DB account using the SQL API, log in to the Azure Portal, select Azure Cosmos DB, and select your account. In the Settings section, click Connection String and set the following values:
- AccountEndpoint: The value should be the Cosmos DB account URL from the Keys blade of the Cosmos DB account.
- AccountKey: In the Azure portal, navigate to the Cosmos DB service and select your Azure Cosmos DB account. From the resource menu, go to the Keys page. Find the PRIMARY KEY value and set Token to this value.
Accessing NoSQL Tables
The provider implements Automatic Schema Discovery that is highly configurable. The following sections outline the provider's defaults and link to ways to further customize.
Flattening Nested JSON
By default, the provider projects columns over the properties of objects. Arrays are returned as JSON strings, by default. You can use the following properties to access array elements, including objects nested in arrays.
- FlattenArrays: Set this property to the number of array elements that you want to return as column values. You can also use this property with FlattenObjects to extract the properties of objects nested in arrays.
FlattenObjects: By default, this is true; that is, the properties of objects and nested objects are returned as columns. When you set FlattenArrays, objects nested in the specified array elements are also flattened and returned as columns.
Other mechanisms for accessing nested objects are detailed in NoSQL Database.
Fine Tuning Data Access
You can use the following properties to gain greater control over Cosmos DB API features and the strategies the provider uses to surface them:
- RowScanDepth: This property determines the number of rows that will be scanned to detect column data types when generating table metadata.
- TypeDetectionScheme: This property allows more control over the strategy implemented by the RowScanDepth property.
GenerateSchemaFiles: This property enables you to persist table metadata in static schema files that are easy to customize, to persist your changes to column data types, for example. You can set this property to "OnStart" to generate schema files for all tables in your database at connection. Or, you can generate schemas as you execute SELECT queries to tables. The resulting schemas are based on the connection properties you use to configure Automatic Schema Discovery.
To use the resulting schema files, set the Location property to the folder containing the schemas.
Customizing the SSL Configuration
By default, the provider attempts to negotiate SSL/TLS by checking the server's certificate against the system's trusted certificate store. To specify another certificate, see the SSLServerCert property for the available formats to do so.
Connecting Through a Firewall or Proxy
To connect set FirewallType, FirewallServer, and FirewallPort. To tunnel the connection, set FirewallType to TUNNEL. To authenticate specify FirewallUser and FirewallPassword. To authenticate to a SOCKS proxy, set FirewallType to SOCKS5.
Troubleshooting the Connection
To show provider activity from query execution to HTTP calls, use Logfile and Verbosity. The examples of common connection errors below show how to use these properties to get more context. Contact the support team for help tracing the source of an error or circumventing a performance issue.
- Authentication errors: Typically, recording a Logfile at Verbosity 4 is necessary to get full details on an authentication error.
- Queries time out: A server that takes too long to respond will exceed the provider's client-side timeout. Often, setting the Timeout property to a higher value will avoid a connection error. Another option is to disable the timeout by setting the property to 0. Setting Verbosity to 2 will show where the time is being spent.
The certificate presented by the server cannot be validated: This error indicates that the provider cannot validate the server's certificate through the chain of trust. (If you are using a self-signed certificate, there is only one certificate in the chain).
To resolve this error, you must verify yourself that the certificate can be trusted and specify to the provider that you trust the certificate. One way you can specify that you trust a certificate is to add the certificate to the trusted system store; another is to set SSLServerCert.