# Adding database connectors
<a name="presto-adding-db-connectors"></a>

You can use configuration classifications to configure JDBC connector properties when you create a cluster. Configuration classifications begin with `presto-connector`, for example, `presto-connector-postgresql`. The available configuration classifications depend on the Amazon EMR release version. For the configuration classifications available with the most recent release version, see [5.36.2 configuration classifications](emr-5362-release.md#emr-5362-class) for Amazon EMR 5.36.2. If you are using a different version of Amazon EMR, see [Amazon EMR 5.x release versions](emr-release-5x.md) for the configuration classifications. For more information about the properties that can be configured with each connector, see [https://prestodb.io/docs/current/connector.html](https://prestodb.io/docs/current/connector.html). 

**Example —configuring a cluster with the PostgreSQL JDBC connector**  
To launch a cluster with the PostgreSQL connector installed and configured, first create a JSON file that specifies the configuration classification—for example, `myConfig.json`—with the following content, and save it locally.  
Replace the connection properties as appropriate for your setup and as shown in the [PostgreSQL connector](https://prestodb.io/docs/current/connector/postgresql.html) topic in Presto Documentation.  

```
[
  {
    "Classification": "presto-connector-postgresql",
    "Properties": {
      "connection-url": "jdbc:postgresql://{{example.net}}:5432/{{database}}",
      "connection-user": "{{MYUSER}}",
      "connection-password": "{{MYPASS}}"
    },
    "Configurations": []
  }
]
```
When you create the cluster, reference the path to the JSON file using the `--configurations` option as shown in the following example, where `myConfig.json` is in the same directory where you run the command:  

```
aws emr create-cluster --name PrestoConnector --release-label emr-5.36.2 --instance-type m5.xlarge \
--instance-count 2 --applications Name=Hadoop Name=Hive Name=Pig Name=Presto \
--use-default-roles --ec2-attributes KeyName={{myKey}} \
--log-uri s3://{{amzn-s3-demo-bucket}}/logs --enable-debugging \
--configurations file://myConfig.json
```