PHP DataServices 2 Minutes Introduction

We use the term DataServices for exposing a Database as a WebService. PHP DataServices library make this task easy by providing a very simple API to the developers.

The API is designed to let the service developer to provide the database configurations, input message format, output message format and the SQL query information. So reading and parsing the input SOAP message, building the response SOAP message from the queried data, serving the WSDL and providing the Database independent layer (with the help of PDO extensions) are done by the Dataserivce library.

Configurations

You give your database configurations in this format.

// database configuraitons
$config = array(
      "db" => "mysql", //your sql
      "username" => DB_USERNAME, //your username
      "password" => DB_PASSWORD, //your password
      "dbname" => "ds", //your database name
      "dbhost" => "localhost"); //your database host

Input Format

You have to declare the names and the types of the content of your input message. This is needed to generate the WSDL and invoke the database query with parameters.

// input format array(param_name => SQL_TYPE)
$inputFormat = array("customerNumber" => "INT");

Output Format

You can customize your response SOAP message by providing the names of the wrapper elements  for both the message and the rows.

// output format, plese check the API from http://wso2.org/wiki/display/wsfphp/API+for+Data+Services+Revised
$outputFormat = array("resultElement" => "Orders", //the name of the wrapper element of the message
                      "rowElement" => "Order", //the name of the wrapper element of each row
                      "elements" => array( "order-number" => "OrderNumber",
                                           "order-date" => "OrderDate",
                                           "status" => "status"));

Create the Query

The query in the PHP dataserivces term is not just the SQL query that you are familiar in accessing a database, It contains the input and output formats in addition to the actual SQL query to invoke.

// sql statment to execute
$sql="select o.OrderNumber, o.OrderDate, o.status from Customers c, Orders o where c.customerNumber=o.customerNumber and c.customerNumber=?";

// operations are consist of inputFormat (optional), outputFormat(required), sql(sql), input_mapping(optional)
$operations = array("customerOrders" =>array("inputFormat" => $inputFormat, "outputFormat" => $outputFormat, "sql" => $sql));

DataService object

Finally you create the DataService object with the provided configurations and the query information.

require_once("wso2/DataServices/DataService.php");

$my_data_service = new DataService(array("config" => $config,"operations" => $operations));

$my_data_service->reply();