The Web Services Database (WSDB) is internally represented as a series of Tcl namespaces, configuration variables and dynamically generated code. This structure allows for maximum introspection, which is used to build and manage web services and to create and validate documents.

Following is the current structure for the Web Services Database. One fact to keep in mind is that in XML Schema, simpleTypes and complexTypes can have the same name, since they are in different XML namespaces. To reflect this fact, simpleTypes and complexTypes are maintained in separate Tcl namespaces. In general, the Web Services Database is partitioned into a hierarchy of Tcl namespaces which follow the pattern:

 :: wsdb
   :: { structural component type }
     :: { XML Namespace Alias }
       :: { component name }
         :: { variable children }

# Main Tcl Namespace 
::wsdb

# structural component type: schema (XML Schema Information)
::wsdb::schema

# WSDB supports multiple XML Schema Namespaces.
# XML Namespaces are intended to be univerally unique and use a
#  short text string, called a prefix in an instance document.
# WSDB uses a similar concept, called an alias which maps the
#  unique XML Namespace to a internally unique text string.
# For example the XML Schema Namespace mapping is:
#  xsd = http://www.w3.org/2001/XMLSchema

# Schema to Alias Mappings (variable):
$::wsdb::schema::aliasMap

# Built in schema: XML Schema (alias = xsd):
::wsdb::schema::xsd

# structural component type: simpleTypes
::wsdb::types

# simpleTypes in xsd (http://www.w3.org/2001/XMLSchema)
::wsdb::types::xsd

# xsd component: string 
# The namespace contains variables and a procedure to validate 
::wsdb::types::xsd::string

# structural component type: complexTypes (elements)
::wsdb::elements

# element component in stockquoter (url:tcl:stockquoter)
::wsdb::elements::stockquoter::StockQuote

#
# The following component types are specific to WSDL
#

# structural component type: messages 
::wsdb::messages

# Messages point to some individual element (from any namespace)

# one message in stockquoter (alias) namespace:
::wsdb::messages::stockquoter::StockRequest

# structural component type: operations
::wsdb::operations

# Operations provide the key interface between XML Structures
#  and internal Tcl procedures. An operation ties togeather:
#  1. Input message type 
#  2. Conversion of message to Tcl structures
#  3. Invocation of Tcl procedure
#  4. Conversion of Tcl results to specific format
#  5. Creation of result document via 'new' procedure:
$::wsdb::elements::stockquoter::StockQuote::new [list of child elements] 

# one operation 
# Maintains information and procedures necessary for invocation: 
::wsdb::operations::stockquoter::StockQuoteOperation

# structural component type: portTypes
# portTypes represent a collection of operations which are:
# 1. Free of transport bindings (SOAP) and possibly,
# 2. Free of instance representation (RPC vs Document):
::wsdb::portTypes

# one portType
::wsdb::porttypes::stockquoter::StockQuotePortType


# structural component type: bindings
# portTypes can be bound to multiple protocols and instance
#  representations. Currently only document/literal is supported.  
::wsdb::bindings

# Bindings can only be reused at the port level, so internal
# namespace distinctions no longer apply. Bindings are also unique,
# it is illegal to combine the same portType to the same binding
# more than once.
 
# one binding
::wsdb::bindings::StockQuoteSoapBind

# structural component type: ports
# Ports provide a physical URL for the associated binding.
# ports
::wsdb::ports

# one port
::wsdb::ports::StockQuotePort


# structural component type: services
# A service can contain multiple ports, however, since
# tWSDL can run multiple services at the same time, it is more common
# to have one port per service:
::wsdb::services

# one service
::wsdb::services::StockQuoteService


# tWSDL component: server
::wsdb::servers

# A tWSDL server defines the external targetNamespace.
# A server is associated with a single WSDL file, and can contain
#  multiple services, although there is usually no need to do this.
# The server namespace also maintains information on how to start up
# a listener, which host names and which path to use.

# one server
::wsdb::servers::StockQuoter



 

The sequence of namespaces listed above reflects the order in which data is added to the Web Services DB. It also reflect the information available to API calls. As the database is filled, future API calls can rely on this information, and refer to it by name only. In addition, the order reflects the fact that abstract descriptions can be reused by later API calls, essentially to branch off. For instance, once an abstract type is defined, it can be used by all future services. Operations can be combined into different portTypes. The same portType could be bound to different ports in different services.