JDBC Driver for PostgreSQL

Build 22.0.8462

Establishing a Connection

Creating a JDBC Data Source

You can create a JDBC data source to connect from your Java application. Creating a JDBC data source based on the CData JDBC Driver for PostgreSQL consists of three basic steps:

  • Add the driver JAR file to the classpath. The JAR file is located in the lib subfolder of the installation directory. Note that the .lic file must be located in the same folder as the JAR file.
  • Provide the driver class. For example: 
    cdata.jdbc.postgresql.PostgreSQLDriver
  • Provide the JDBC URL. For example: 
    jdbc:postgresql:User=postgres;Password=admin;Database=postgres;Server=127.0.0.1;Port=5432

or

jdbc:cdata:postgresql:User=postgres;Password=admin;Database=postgres;Server=127.0.0.1;Port=5432

    The second format above can be used whenever there is a conflict in your application between drivers using the same URL format to ensure you are using the CData driver. The URL must start with either "jdbc:postgresql:" or "jdbc:cdata:postgresql:" and can include any of the connection properties in name-value pairs separated with semicolons.

Connecting to PostgreSQL

The following connection properties are usually required to connect to PostgreSQL.

  • Server: The host name or IP of the server hosting the PostgreSQL database.
  • User: The user which will be used to authenticate with the PostgreSQL server.

You can also optionally set the following:

  • Database: The database to connect to when connecting to the PostgreSQL Server. If this is not set, the user's default database will be used.
  • Port: The port of the server hosting the PostgreSQL database. 5432 by default.

Standard

Unless you select another scheme, Password is the default authentication mechanism the driver uses to connect to PostgreSQL Server.

To use standard authentication, set the AuthScheme to Password to connect to PostgreSQL with login credentials.

Then, to authenticate, set the Password associated with the authenticating user.

pg_hba.conf Auth Schemes

There are subtypes of the Password authentication scheme supported by the driver which must be enabled in the pg_hba.conf file on the PostgreSQL server.

See the PostgreSQL documentation for more information about authentication setup on the PostgreSQL Server.

MD5

The driver can authenticate by verifying the password with MD5. This authentication method must be enabled by setting the auth-method in the pg_hba.conf file to md5.

SASL

The driver can authenticate by verifying the password with SASL (particularly, SCRAM-SHA-256). This authentication method must be enabled by setting the auth-method in the pg_hba.conf file to scram-sha-256.

Azure

Methods available for connecting to PostgreSQL with Microsoft Azure include:

  • Azure Active Directory OAuth
  • Azure Active Directory Password
  • Azure Active Directory MSI

Azure AD

Azure AD is a connection type that leverages OAuth to authenticate. OAuth requires the authenticating user to interact with PostgreSQL using an internet browser. The driver facilitates this in several ways as described below. Set your AuthScheme to AzureAD. All AzureAD flows assume that you have done so.

Desktop Applications

CData provides an embedded OAuth application that simplifies OAuth desktop Authentication. Alternatively, you can create a custom OAuth application. See Creating a Custom AzureAD App for information about creating custom applications and reasons for doing so.

For authentication, the only difference between the two methods is that you must set two additional connection properties when using custom OAuth applications.

After setting the following connection properties, you are ready to connect:

  • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
  • OAuthClientId: (custom applications only) Set this to the client Id in your application settings.
  • OAuthClientSecret: (custom applications only) Set this to the client secret in your application settings.
  • CallbackURL: Set this to the Redirect URL in your application settings.

When you connect the driver opens the OAuth endpoint in your default browser. Log in and grant permissions to the application. The driver then completes the OAuth process:

  1. Extracts the access token from the callback URL and authenticates requests.
  2. Obtains a new access token when the old one expires.
  3. Saves OAuth values in OAuthSettingsLocation that persist across connections.

Web Applications

When connecting via a Web application, you need to register a custom OAuth app with PostgreSQL. See Creating a Custom AzureAD App. You can then use the driver to get and manage the OAuth token values. Get an OAuth Access Token

Set one of the following connection properties groups depending on the authentication type to obtain the OAuthAccessToken:

  1. Authenticating using a Client Secret
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthClientSecret: Set this to the client secret in your app settings.
  2. Authenticating using a Certificate
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthJWTCert: Set this to the JWT Certificate store.
    • OAuthJWTCertType: Set this to the type of the certificate store specified by OAuthJWTCert.

You can then call stored procedures to complete the OAuth exchange:

  1. Call the GetOAuthAuthorizationUrl stored procedure. Set the AuthMode input to WEB and set the CallbackURL input to the Redirect URI you specified in your app settings. If necessary, set the Permissions parameter to request custom permissions.

    The stored procedure returns the URL to the OAuth endpoint.

  2. Open the URL, log in, and authorize the application. You are redirected back to the callback URL.
  3. Call the GetOAuthAccessToken stored procedure. Set the AuthMode input to WEB. Set the Verifier input to the "code" parameter in the query string of the callback URL. If necessary, set the Permissions parameter to request custom permissions.

To connect to data, set the OAuthAccessToken connection property to the access token returned by the stored procedure. When the access token expires after ExpiresIn seconds, call GetOAuthAccessToken again to obtain a new access token.

Headless Machines

To configure the driver to use OAuth with a user account on a headless machine, you need to authenticate on another device that has an internet browser.

  1. Choose one of these two options:

    • Option 1: Obtain the OAuthVerifier value as described in "Obtain and Exchange a Verifier Code" below.
    • Option 2: Install the driver on another machine and transfer the OAuth authentication values after you authenticate through the usual browser-based flow, as described in "Transfer OAuth Settings" below.

  2. Then configure the driver to automatically refresh the access token from the headless machine.

Option 1: Obtain and Exchange a Verifier Code

To obtain a verifier code, you must authenticate at the OAuth authorization URL.

Follow the steps below to authenticate from the machine with an internet browser and obtain the OAuthVerifier connection property.

  1. Choose one of these options:

    • If you are using the Embedded OAuth Application click PostgreSQL OAuth endpoint to open the endpoint in your browser.
    • If you are using a custom OAuth application, create the Authorization URL by setting the following properties:
      • InitiateOAuth: Set to OFF.
      • OAuthClientId: Set to the client Id assigned when you registered your application.
      • OAuthClientSecret: Set to the client secret assigned when you registered your application.
      Then call the GetOAuthAuthorizationUrl stored procedure with the appropriate CallbackURL. Open the URL returned by the stored procedure in a browser.

  2. Log in and grant permissions to the driver. You are then redirected to the callback URL, which contains the verifier code.
  3. Save the value of the verifier code. Later you will set this in the OAuthVerifier connection property.
Next, you need to exchange the OAuth verifier code for OAuth refresh and access tokens. Set the following properties:

On the headless machine, set the following connection properties to obtain the OAuth authentication values:

  • InitiateOAuth: Set this to REFRESH.
  • OAuthVerifier: Set this to the verifier code.
  • OAuthClientId: (custom applications only) Set this to the client Id in your custom OAuth application settings.
  • OAuthClientSecret: (custom applications only) Set this to the client secret in the custom OAuth application settings.
  • OAuthSettingsLocation: Set this to the path to the file where the driver saves the OAuth token values that persist across connections.

After the OAuth settings file is generated, you need to re-set the following properties to connect:

  • InitiateOAuth: Set this to REFRESH.
  • OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
  • OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
  • OAuthSettingsLocation: Set this to the file containing the encrypted OAuth authentication values. Make sure this file grants read and write permissions to the driver to enable the automatic refreshing of the access token.

Option 2: Transfer OAuth Settings

Prior to connecting on a headless machine, you need to create and install a connection with the driver on a device that supports an internet browser. Set the connection properties as described in "Desktop Applications" above.

After completing the instructions in "Desktop Applications", the resulting authentication values are encrypted and written to the path specified by OAuthSettingsLocation. The default filename is OAuthSettings.txt.

Once you have successfully tested the connection, copy the OAuth settings file to your headless machine.

On the headless machine, set the following connection properties to connect to data:

  • InitiateOAuth: Set this to REFRESH.
  • OAuthClientId: (custom applications only) Set this to the client Id assigned when you registered your application.
  • OAuthClientSecret: (custom applications only) Set this to the client secret assigned when you registered your application.
  • OAuthSettingsLocation: Set this to the path to your OAuth settings file. Make sure this file gives read and write permissions to the driver to enable the automatic refreshing of the access token.

Admin Consent

Admin consent refers to when the Admin for an Azure Active Directory tenant grants permissions to an application which requires an admin to consent to the use case. The embedded app within the CData JDBC Driver for PostgreSQL, contains no permissions that require admin consent. Therefore, this information applies only to custom applications.

Admin Consent Permissions

When creating a new AzureAD app in the Azure Portal, you must specify which permissions the app will require. Some permissions may be marked as "Admin Consent Required". For example, all Groups permissions require Admin Consent. If your app requires admin consent, there are a couple of ways this can be done.

The easiest way to grant admin consent is to just have an admin log into portal.azure.com and navigate to the app you have created in App Registrations. Under API Permissions, click Grant Consent for your app to have permissions on the tenant under which it was created.

If your organization has multiple tenants or you need to grant application permissions for other tenants outside your organization, use the GetAdminConsentURL stored procedure to generate the Admin Authorization URL. Unlike the GetOAuthAuthorizationUrl, there will be no important information returned from this endpoint. After the OAuth application is successfully authorized, it returns a Boolean indicating that permissions have been granted.

After the administrator has approved the OAuth Application, you can continue to authenticate.

Client Credentials

Client credentials refers to a flow in OAuth where there is no direct user authentication taking place. Instead, credentials are created for just the app itself. All tasks taken by the app are done without a default user context. This makes the authentication flow a bit different from standard.

Client OAuth Flow

All permissions related to the client oauth flow require admin consent. This means the app embedded with the CData JDBC Driver for PostgreSQL cannot be used in the client oauth flow. You must create your own OAuth app in order to use client credentials. See Creating a Custom AzureAD App for more details.

In your App Registration in portal.azure.com, navigate to API Permissions and select the Microsoft Graph permissions. There are two distinct sets of permissions - Delegated and Application permissions. The permissions used during client credential authentication are under Application Permissions. Select the permissions you require for your integration.

You are ready to connect after setting one of the connection properties groups depending on the authentication type.

  1. Authenticating using a Client Secret
    • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
    • AzureTenant: Set this to the tenant you wish to connect to.
    • OAuthGrantType: Set this to CLIENT.
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthClientSecret: Set this to the client secret in your app settings.
  2. Authenticating using a Certificate
    • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
    • AzureTenant: Set this to the tenant you wish to connect to.
    • OAuthGrantType: Set this to CLIENT.
    • OAuthClientId: Set this to the client Id in your app settings.
    • OAuthJWTCert: Set this to the JWT Certificate store.
    • OAuthJWTCertType: Set this to the type of the certificate store specified by OAuthJWTCert.

Authentication with client credentials takes place automatically like any other connection, except there is no window opened prompting the user. Because there is no user context, there is no need for a browser popup. Connections will take place and be handled internally.

Note: Azure PostgreSQL Flexible servers are not supported. Only Azure PostgreSQL Single Server instances are supported.

Ensure that an Active Directory admin has been set in the Azure PostgreSQL instance (Active Directory admin -> Set admin).

Next, set the following to connect:

  • User: Set this to the Azure Active Directory user you granted access to the Azure PostgreSQL server.
  • AzureTenant: Set this to the Directory (tenant) ID, found on the Overview page of the OAuth app used to authenticate to PostgreSQL on Azure.
  • Server: Set this to the Server name of the Azure PostgreSQL server, found on the Overview page of the Azure PostgreSQL instance.
  • Database: Set this to the database you'd like to connect to on the Azure PostgreSQL instance.
  • Port: The port of the server hosting the PostgreSQL database. 5432 by default.
  • InitiateOAuth: Set this to GETANDREFRESH.
  • OAuthClientId: Set this to the Application (client) ID, found on the Overview page of the OAuth app used to authenticate to PostgreSQL on Azure.
  • OAuthClientSecret: Set this to the Value of the client secret, generated at the Certificates and secrets page of the authenticating OAuth app.
  • CallbackURL: Set this to the Redirect URI you specified during the creation of your OAuth app.

Azure Password

To connect using your Azure credentials directly, specify the following connection properties:

  • AuthScheme: Set this to AzurePassword.
  • User: Set this to your user account you use to connect to Azure.
  • Password: Set this to the password you use to connect to Azure.
  • AzureTenant: Set this to the Directory (tenant) ID, found on the Overview page of the OAuth app used to authenticate to PostgreSQL on Azure.
  • Server: Set this to the Server name of the Azure PostgreSQL server, found on the Overview page of the Azure PostgreSQL instance.
  • Database: Set this to the database you'd like to connect to on the Azure PostgreSQL instance.
  • Port: The port of the server hosting the PostgreSQL database. 5432 by default.

GCP Service Account

To authenticate to your PostgreSQL Google SQL Cloud Instance using a service account, you must create a new service account and have a copy of the accounts certificate. If you do not already have a service account, you can create one by following the procedure in Creating a Custom AzureAD App. For a JSON file, set these properties:

  • AuthScheme: Set this to GCPServiceAccount.
  • InitiateOAuth: Set this to GETANDREFRESH.
  • OAuthJWTCertType: Set this to GOOGLEJSON.
  • OAuthJWTCert: Set this to the path to the .json file provided by Google.
  • OAuthJWTSubject: (optional) Only set this value if the service account is part of a GSuite domain and you want to enable delegation. The value of this property should be the email address of the user whose data you want to access.

For a PFX file, set these properties instead:

  • AuthScheme: Set this to GCPServiceAccount.
  • InitiateOAuth: Set this to GETANDREFRESH.
  • OAuthJWTCertType: Set this to PFXFILE.
  • OAuthJWTCert: Set this to the path to the .pfx file provided by Google.
  • OAuthJWTCertPassword: (optional) Set this to the .pfx file password. In most cases you must provide this since Google encrypts PFX certificates.
  • OAuthJWTCertSubject: (optional) Set this only if you are using a OAuthJWTCertType which stores multiple certificates. Should not be set for PFX certificates generated by Google.
  • OAuthJWTIssuer: Set this to the email address of the service account. This address will usually include the domain iam.gserviceaccount.com.
  • OAuthJWTSubject: (optional) Only set this value if the service account is part of a GSuite domain and you want to enable delegation. The value of this property should be the email address of the user whose data you want to access.

MSI

If you are running PostgreSQL on an Azure VM, you can leverage Managed Service Identity (MSI) credentials to connect:

  • AuthScheme: Set this to AzureMSI.
  • User: Set this to the Azure PostgreSQL user that maps to your managed service identity. Provide this in the format myuser@myservername, where myservername doesn't include the ".postgres.database.azure.com" part.
  • Server: Set this to the Server name of the Azure PostgreSQL server, found on the Overview page of the Azure PostgreSQL instance.
  • Database: Set this to the database you'd like to connect to on the Azure PostgreSQL instance.
  • Port: The port of the server hosting the PostgreSQL database. 5432 by default.

The MSI credentials are automatically obtained for authentication.

Amazon Web Services

Obtain AWS Keys

To obtain the credentials for an IAM user, follow the steps below:

  1. Sign into the IAM console.
  2. In the navigation pane, select Users.
  3. To create or manage the access keys for a user, select the user and then go to the Security Credentials tab.

To obtain the credentials for your AWS root account, follow the steps below:

  1. Sign into the AWS Management console with the credentials for your root account.
  2. Select your account name or number and select My Security Credentials in the menu that is displayed.
  3. Click Continue to Security Credentials and expand the "Access Keys" section to manage or create root account access keys.

AWS IAM Roles

In many situations it may be preferable to use an IAM role for authentication instead of the direct security credentials of an AWS root user.

To authenticate as an AWS role, set the following:

  • AuthScheme: Set this to AwsIAMRoles.
  • User: Set this to the AWS-hosted PostgreSQL user that you granted the aws_iam role to. This user should map to an AWS user that has a role containing a policy which includes the rds-db:connect permission.
  • AWSRoleARN: Specify the Role ARN for the role attached to the authenticating IAM user. This will cause the driver to attempt to retrieve credentials for the specified role.
  • AWSAccessKey: The access key of the authenticating IAM user.
  • AWSSecretKey: The secret key of the authenticating IAM user.

Note: Roles may not be used when specifying the AWSAccessKey and AWSSecretKey of an AWS root user.

Kerberos

The authentication with Kerberos is initiated by PostgreSQL Server when the CData JDBC Driver for PostgreSQL is trying to connect to it. You should setup Kerberos on the PostgreSQL Server to activate this authentication method. Once you have Kerberos authentication setup on the PostgreSQL Server, see Using Kerberos for details on how to authenticate with Kerberos by the driver.

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Build 22.0.8462