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Web services are applications stored on web servers that are accessed through standard web protocols (HTTP, SOAP) and data formats (HTML, XML...), whatever the systems and programming languages. PowerDesigner supports modeling for both the SOAP protocol, in which queries are encapsulated into services, and HTTP, where operations are invoked directly.

If you use web services to query databases, you no longer need database drivers. The following example shows the result of an HTTP request for a database web service:

Web services comprise a set of operations, each of which contains a SQL query for retrieving data from a database. Web parameters are the parameters which appear in the SQL statements, and result columns display the results. These objects have no symbols, and appear only in the Browser. Web services can be modeled for the following DBMSs:
  • SAP® SQL Anywhere® v9 and over.
  • SAP® Adaptive Server® Enterprise v15 and over.
  • SAP® IQ v12.6 and over.
  • IBM DB2 v8.1 and over - Document Access Definition Extension (DADX) files specify Web services through a set of operations defined by SQL statements or Document Access Definition (DAD) files, which specify the mapping between XML elements and DB2 tables (see Generating Web Services for IBM DB2 and XML Modeling > Working with XML and Databases > Generating a DAD File for IBM DB2.

You can test a Web service of type DISH or SOAP from within your model by right-clicking its Browser entry and selecting Show WSDL. You can test a web service operation belonging to a Web service of another type by right-clicking the operation and selecting Test Web Service Operation. Review the generated URL and then click OK to display the WSDL file (for SOAP) or results (for RAW) in your Web browser.

You can import a Web service as a service provider into a Business Process Model (BPM) to define the links between a concrete implementation of service interfaces and operations and their abstract definition (see Business Process Modeling > Service Oriented Architecture (SOA) > Service Providers (BPM)).


In this section:
    Creating a Web Service
    You can create a web service from the Browser or Model menu.
    Web Service Properties
    To view or edit a web service's properties, double-click its Browser or list entry. The property sheet tabs and fields listed here are those available by default, before any customization of the interface by you or an administrator.
    Web Operations (PDM)
    A web operation allows you to define the SQL statement of a web service and to display its parameters and result columns.
    Web Parameters (PDM)
    Web parameters are part of the SQL statement defined in the Implementation tab of a web operation property sheet, and are listed on its Parameters tab.
    Web Result Columns (PDM)
    Result columns are part of the SQL statement defined in the Implementation tab of a web operation property sheet, and are listed on its Result Columns tab. They belong to a table in the target database.
    Generating Web Services for SQL Anywhere, ASE, and IQ
    You can generate database web services to a script or to a live database connection.
    Generating Web Services for IBM DB2
    For IBM DB2 Web services, PowerDesigner can generate Document Access Definition Extension (DADX) files.
    Reverse Engineering Web Services
    You can reverse engineer Web services from a SQL Anywhere, ASE, and IQ database to a PDM. You can reverse engineer web services into a new or existing PDM from a script or live database connection via the Database Reverse Engineering dialog box.