Establishing a Connection
You can create and manage connections with the Data Explorer and the FireDAC Connection Editor wizards. See Connection Definitions for more information on creating connections from code and creating persistent, private, or temporary connections.
Connecting to HDFS
In order to connect, set the following connection properties:
- Host: Set this value to the host of your HDFS installation.
- Port: Set this value to the port of your HDFS installation. Default port: 50070
Authenticating to HDFS
There are two authentication methods available for connecting to the HDFS data source, the Anonymous Authentication and the and Negotiate (Kerberos) Authentication.
In some situations, HDFS may be connected to without any authentication connection properties. To do so, simply set the AuthScheme to None (default).
Authenticate using Kerberos
When authentication credentials are required, authentication over Kerberos may be used. Please see Using Kerberos for details on how to authenticate with Kerberos.
Using the FireDAC Connection Editor
Complete the following steps to use the FireDAC Connection Editor to assign a HDFS connection to a TFDConnection object:
- Open a project and drop a TFDPhysCDataHDFSDriverLink from the Tool Palette onto the Form Designer.
- Drop a TFDConnection object onto the Form Designer.
- Double-click the TFDConnection and select CDataHDFS in the Driver Id menu.
- Define the necessary connection properties.
- To execute ad-hoc SQL statements based on this connection, enter SQL commands on the SQL Script tab.
- In the Form Designer, select the TFDConnection object and set the Connected property to true.
Using the Data Explorer
Complete the following steps to use the Data Explorer to define persistent connections that can be shared across applications and projects:
- Click View > Tool Windows > Data Explorer in RAD Studio and expand the FireDAC node.
- Right-click the CData HDFS Data Source node and click Add New Connection.
- Enter a name for the connection. The FireDAC Connection Editor opens.
Working with Persistent Connections
The connections you define in the Data Explorer can be assigned to a TFDConnection object by specifying the connection name in the TFDConnection object's ConnectionDefName property.
Browsing Data and Metadata
The Data Explorer also provides options for browsing HDFS objects at design time:
- Expand the CData HDFS Data Source node in the Data Explorer to view the defined connections.
- Expand a connection node to find the database objects available for a connection.
- Drill down to a database object to find metadata such as primary keys.
- To display data, double-click a table or view or right-click and click View.