Stored functions and stored procedures that act as web service clients can be declared with parameters, just like other types of function or procedures. These parameter values, unless used during parameter substitution, are passed as part of the HTTP or SOAP request.
In addition, parameters can be used to replace placeholders within the body of the stored function or stored procedure at the time the function or procedure is called. If no placeholders for a particular variable exist, the parameter and its value are passed as part of the request. Parameters and values used for substitution in this manner are not passed as part of the web service request.
Parameter data type conversion