Interview Questions

Q: What do you mean by Reset Content Descriptor node?

A: Reset Content Descriptor node request to parse the message with different parser, leaving the message content unchanged.

Q: What is the difference between an MQ Get node and MQ Input node?

A: The MQ Get node reads a message from a specified queue, and establishes the processing environment for the message. Whereas, The MQ Input node receives a message from a WebSphere MQ message queue that is defined on the queue manager of the broker.

   You can use an MQ Get node anywhere in a message flow, unlike an MQ Input node, which you can use only as the first node in a message    flow.

Q: What is the difference between SOAP Request node and SOAP Async Request node?

A: The SOAP Async Request node sends a Web service request, but the node does not wait for the associated Web service response to be received. This asynchronous functionality enables multiple outbound requests to be made almost in parallel because the outbound    request is not blocked waiting for the response.

   Whereas, The SOAP Request node is a synchronous request and response node, which blocks processing after sending the request until    the response is received.

           

Q: What is the difference between mapping node and Compute node transformation?

A: In Compute node you can transform the message by coding ESQL in the ESQL resource file attached. Whereas, In mapping node you can    use graphical maps to transform input message by associating an input message model such as a DFDL or XML schema, or an MRM Message    Set and an output message model.

   In compute node you can change the entire message even the header assemblies. But, in mapping node you can change the message    assembly, message body, and properties.

Q: What is the difference between Input and MQ Input node?

A: Use the Input node as an in terminal for an embedded message flow (a sub flow).The MQ Input node receives a message from a WebSphere    MQ message queue that is defined on the queue manager of the broker. It is the first node of your message flow.

Q: What is the purpose or use of compute node?

A: The Compute node is used to: 

•    Build a new message using a set of assignment statements
•    Copy messages between parser
•    Convert messages from one code set to another
•    Transform messages from one format to another 

Q: How the interaction with Database does take place using Compute node?

A: In Data Source specify the name by which the appropriate database is known on the system on which this message flow is to execute.

           

Q: Difference between try catch node and throw node?

A: Include a Throw node to force an error path through the message flow if the content of the message contains unexpected data.

   If a downstream node (which can be a Throw node) throws an exception, the Try Catch node catches it and routes the original message    to its Catch terminal. Connect the Catch terminal to further nodes to provide error processing for the message after an exception.

           

Q: How will input messages with different - different delimiters between the fields are handled in WMB?

A: Using MRM domain we can input messages with different - different delimiters between the fields in WMB.

           

Q: What do you mean by depth of a Queue?

A: Queue depth, is the number of pending input/output messages in a queue.

Q: How can we know the current depth of a queue?

A: Using MQSC property CURDEPTH we can know the current depth of a queue.

Q: Message Broker supports what all formats?

A: Message Broker supports XML, TDS, CSV, CWF, EDIFACT, SWIFT, COBOL formats

Q: What all nodes use ESQL?

A: ESQL can be used with the Compute, Database, and Filter nodes.

           

Q: What is ESQL?

A: Extended Structured Query Language (ESQL) is a programming language based on Structured Query Language (SQL), which is commonly    used with relational databases such as DB2. ESQL extends the constructs of the SQL language to provide support for you to work with    both message and database content.

           

Q: What functionality ESQL provides?

A: Through ESQL you can 

•    Change the message content.
•    Modify an existing message
•    Create a new message
•    Add dynamic terminals
•    Route a message
•    Propagate a new request 

Q: What are the types of variables in ESQL?

A: ESQL variables can be described as external variables, normal variables, or shared variables.

Q: What are external variables, normal variables or shared variables?

A: External variables: 

• Also known as user defined properties.
• Exist for entire life time of a message flow and are visible to all messages passed through the flow.
• You have to assign an initial value at the time of declaring an external variable and then can modify the initial value at deployment time by using the BAR editor.   

Normal Variables: 

• Have lifetime of just one message pass through a node.
• Visible to the message only in which it was defined.
• To define, omit both EXTERNAL and SHARED keyword. 

Shared variable: 

• Used for implementing in-memory cache in the message flow.
• Have a long life time and are visible to multiple messages pass through the flow.
• Exist for the lifetime of Execution group, lifetime of flow or node, lifetime of node’s     ESQL that declares the variable.
• Initialized when the first message pass through the node or flow after broker start-up. 

Q: What are patterns?

A: A pattern captures a tested solution to a commonly recurring problem, addressing the objectives that you want to achieve.

           

Q: What are the benefits of using patterns?

A: Patterns provide the following benefits:

• Give you guidance for the implementation of solutions
• Increase development efficiency, because resources are generated from a set of predefined templates
• Result in higher quality solutions, through reuse of assets and common implementation of programming approaches, such as error handling and logging

Q: How do you ensure that messages do not lose?

A: 

For application and internal messages traveling across WebSphere MQ, two techniques protect against message loss: 

• Message persistence - If a message is persistent, WebSphere MQ ensures that it is not lost when a failure occurs, by copying it to    disk.
• Sync point control - An application can request that a message is processed in a synchronized unit-of-work. 

Q: How to use functions in your e SQL code?

A: Use CALL keyword to call functions or methods.

           

Q: What are the ways in which you can access databases from a message flow?

A: 

• You can access a database from a message flow in two ways:
• You can design a message flow that responds to events generated by the database.