Web Client Application Development

SAP Sybase IQ databases can act as web client applications to access SAP Sybase IQ hosted web services or web services hosted on third party web servers. SAP Sybase IQ web client applications are created by writing stored procedures and functions using configuration clauses, such as the URL clause that specifies the web service target endpoint. Web client procedures do not have a body, but in every other way are used as any other stored procedure. When called, a web client procedure makes an outbound HTTP or SOAP request. A web client procedure is restricted from making an outbound HTTP request to itself; it cannot call a localhost SAP Sybase IQ web service running on the same database.

For detailed examples of web service applications, see the %ALLUSERSPROFILE%\SybaseIQ\samples\SQLAnywhere\HTTP directory.

• Web Client Function and Procedure Requirements and Recommendations
  Web service client procedures and functions require the definition of a URL clause to identify the web service endpoint. A web service client procedure or function has specialized clauses for configuration but is used like any other stored procedure or function in every other respect.
• Variables Supplied to Web Services
  Variables can be supplied to a web service in various ways depending on the web service type.
• Variables Accessed from Result Sets
  Web service client calls can be made with stored functions or procedures. If made from a function, the return type must be of a character data type, such as CHAR, VARCHAR, or LONG VARCHAR. The body of the HTTP response is the returned value. No header information is included. Additional information about the request, including the HTTP status information, is returned by procedures. So, procedures are preferred when access to additional information is desired.
• Substitution Parameters Used for Clause Values
  Declared parameters to a stored procedure or function are automatically substituted for placeholders within a clause definition each time the stored procedure or function is run. Substitution parameters allow the creation of general web service procedures that dynamically configure clauses at run time. Any substrings that contain an exclamation mark '!' followed by the name of one of the declared parameters is replaced by that parameter's value. In this way one or more parameter values may be substituted to derive one or more clause values at runtime.