Access HDFS Data in PHP through Connect Server

You can use CData Connect Server to access HDFS data from SQL Server clients, without needing to perform an ETL or cache data. Follow the steps below to create a virtual SQL Server database for HDFS and connect to HDFS data in real time through PHP's standard SQL Server interface, i.e. sqlsrv_connect.

CData Connect Server provides a pure SQL Server interface for HDFS, allowing you to easily build reports from live HDFS data in PHP — without replicating the data to a natively supported database. As you build visualizations, PHP generates SQL queries to gather data. Using optimized data processing out of the box, CData Connect Server pushes all supported SQL operations (filters, JOINs, etc) directly to HDFS, leveraging server-side processing to quickly return the requested HDFS data.

Create a Virtual SQL Server Database for HDFS Data

CData Connect Server uses a straightforward, point-and-click interface to connect to data sources and generate APIs.

1. Login to Connect Server and click Connections.
2. Select "HDFS" from Available Data Sources.
3. Enter the necessary authentication properties to connect to HDFS.

   In order to authenticate, 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
4. Click Save Changes
5. Click Privileges -> Add and add the new user (or an existing user) with the appropriate permissions.

With the virtual database created, you are ready to connect to HDFS data from PHP.

Connect in PHP

The following examples show how to use object-oriented interfaces to connect and execute queries. Initialize the connection object with the following parameters to connect to the virtual SQL Server database:

• Server name/Host: Specify the remote host location where the service is running.
• Username: Specify the username for a user you authorized in Connect Server.
• Password: Specify the password for the authorized user account.
• Database Name: Specify the name of the virtual database you created for HDFS.
• Port: Specify the port the service is running on, port 1433 in this example.

sqlsrv_connect

<?php
$serverName = "connect_server_url, 1433"; //Connect Server Address, portNumber (default is 1433)
$connectionInfo = array( "Database"=>"HDFS1", "UID"=>"userName", "PWD"=>"password");
$conn = sqlsrv_connect( $serverName, $connectionInfo);

if( $conn ) {
     echo "Connection established.<br>";
}else{
     echo "Connection could not be established.<br>";
     die( print_r( sqlsrv_errors(), true));
}
?>

PDO

<?php
<?php
$user = my_connect_user
$pass = my_connect_pass

$pdo = new PDO("sqlsrv:Server=connect_server_url,1433;Database=HDFS1", $user , $pass);

?>

Query in PHP

With the connection established, you can then access tables. The following steps walk through the example:

1. Query the table; for example, Files. The results will be stored as an associative array in the $result object.
2. Iterate over each row and column, printing the values to display in the PHP page.
3. Close the connection.

sqlsrv_connect

$result = $sqlsrv_connect->query("SELECT FileId, ChildrenNum FROM Files WHERE FileId = '119116'");
while($row = $result->fetch_assoc()) {
  foreach ($row as $k=>$v) {
    echo "$k : $v";
    echo "<br>"; 
  }
}
$sqlsrv_connect->close();

PDO

$result = $pdo->query("SELECT FileId, ChildrenNum FROM Files WHERE FileId = '119116'");
while($row = $result->fetch(PDO::FETCH_ASSOC)) {
  foreach ($row as $k=>$v) {
    echo "$k : $v";
    echo "<br>"; 
  }
}
$result = null;
$pdo = null;

SQL Server Access to HDFS Data using PHP

You have retrieved live HDFS Data using PHP. Now, you can easily access data sources and more — all without replicating HDFS data.

To get SQL data access to 200+ SaaS, Big Data, and NoSQL sources directly from your applications, try CData Connect Server.