About the Simplified Database Routing sample

The Simplified Database Routing sample is based on the scenario of an employee management processing system. The sample demonstrates how to use some of the features provided by IBM Integration Bus.

The Simplified Database Routing sample demonstrates how you can design applications that process self-defining XML messages. XML messages are self-defining because each piece of data is prefixed by a tag name or an attribute name. An XML message definition is in the message itself and is not held anywhere else. Therefore, you can run a message flow by using an XML message without the aid of an external message set.

In this sample the message format is transformed by using the DatabaseRetrieve node. By using the DatabaseRetrieve node, you can use either ESQL or XPath languages to specify the message format of the output message.

The Simplified Database Routing sample performs the following actions:

• Uses a Route node to route the message to different nodes in the message flow based on the presence of specific employee data in the input message. If the employee data is missing, a database lookup operation of the data is performed.
• Uses a DatabaseRetrieve node to add information from a database query to the input message to form a new output message. The query is performed by using a key value that is expected in the original input message.
• Uses a DatabaseRoute node to dynamically route one or more copies of the input message to different parts of the message flow, based on expressions specified in the node. These expressions are applied to the values retrieved from a database query, which is also specified on the node.
• Generates one of the following reply messages based on routing decisions made by the DatabaseRoute node:
  • An employee qualifies for a gift of a clock in recognition of ten years service to the company.
  • A given employee is senior in age to their manager.
  • Confirm that neither of the above two conditions apply to a given employee.
• Generates a reply message indicating that an empty result set is produced if a keyNotFound condition arises from the database query in the DatabaseRoute node.

The following sections describe the Simplified Database Routing sample in more detail:

• The message flow
• The messages
• The database
• The WebSphere MQ queues

The message flow

The Simplified Database Routing sample includes a message flow called SimplifiedDBRouting. The message flow dynamically routes messages and retrieves information about an employee, based on the contents of the test messages. To read more about the message flow, see About the Simplified Database Routing message flow. For more information, see Message flows overview in the IBM Integration Bus documentation.

The messages

The Simplified Database Routing sample processes self-defining, or generic, XML messages. A self-defining XML message carries the information about its content and structure within the message in the form of a document that adheres to the XML specification. A definition of the message is not held anywhere else. When the message flow receives the message, the message is parsed by using the XMLNSC parser according to the XML definitions contained within the message itself.

Four self-defining XML input messages are supplied. You can use these messages to observe how the different content of the messages changes and how the messages are routed in the message flow. The input messages provided have the following content:

• usedbretrievenode: The message requests additional information about a specific employee, providing only their employee number. The employee data satisfies all of the routing conditions set against an employee's details at the end of the flow. See About the usedbretrievenode and usedbretrievenode_nofiltermatch test messages.
• usedbretrievenode_nofiltermatch: The message requests additional information about a specific employee, providing only their employee number. The employee data satisfies none of the routing conditions set against an employee's details at the end of the flow. See About the usedbretrievenode and usedbretrievenode_nofiltermatch test messages.
• bypassdbretrievenode: The message contains information about a specific employee, providing all of the required employee details. The employee data satisfies all of the routing conditions set against an employee's details at the end of the flow. See About the bypassdbretrievenode and bypassdbretrievenode_keynotfound test messages.
• bypassdbretrievenode_keynotfound: The message contains information about a specific employee, providing all of the required employee details. The employee details fail to satisfy any of the routing conditions set against an employee at the end of the flow. The employee details cause the database lookup to fail to find a match, resulting in the message being routed down the keyNotFound route in the message flow. See About the bypassdbretrievenode and bypassdbretrievenode_keynotfound test messages.

The database

The Simplified Database Routing sample uses a database called SROUTEDB, which contains two database tables called DEPARTMENT and EMPLOYEE. The message flow in the sample directly accesses SROUTEDB. For more information about the database in this sample, see About the SROUTEDB database.

The WebSphere MQ queues

The Simplified Database Routing sample message flow interacts with WebSphere MQ local queues. The queues are defined on the WebSphere MQ queue manager that hosts the integration node on which the message flow runs. For more information about the WebSphere MQ queues in this sample, see About the WebSphere MQ queues.

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