S90-09A · Question #29
Service A sends a message to Service B (1). After Service B writes the message contents to Database A (2) it issues a response message back to Service A (3). Service A then sends a message to…
The correct answer is C. The Data Model Transformation pattern can be applied so that data model transformation logic is. Option C is correct because the Data Model Transformation pattern must be applied comprehensively at every point of schema or format incompatibility - at the boundary between Service Inventory A and Service Inventory B (where XML Schema A must be converted to XML Schema B and…
Question
Service A sends a message to Service B (1). After Service B writes the message contents to Database A (2) it issues a response message back to Service A (3). Service A then sends a message to Service C (4). Upon receiving this message, Service C sends a message to Service D (5), which then writes the message contents to Database B (6) and issues a response message back to Service C (7). Service A and Service D are in Service Inventory A. Service B and Service C are in Service Inventory B. You are told that in this service composition architecture, all four services are exchanging invoice- related data in an XML format. However, the services in Service Inventory A are standardized to use a different XML schema for invoice data than the services in Service Inventory B. Also, Database A can only accept data in the Comma Separated Value (CSV) format and therefore cannot accept XML formatted data. Database B only accepts XML formatted data. However, it is a legacy database that uses a proprietary XML schema to represent invoice data that is different from the XML schema used by services in Service Inventory A or Service Inventory B. What steps can be taken to enable the planned data exchange between these four services?
Exhibit
Options
- AThe Data Model Transformation pattern can be applied so that data model transformation logic is
- BThe Data Model Transformation pattern can be applied so that data model transformation logic is
- CThe Data Model Transformation pattern can be applied so that data model transformation logic is
- DNone of the above.
How the community answered
(40 responses)- A5% (2)
- B10% (4)
- C63% (25)
- D23% (9)
Explanation
Option C is correct because the Data Model Transformation pattern must be applied comprehensively at every point of schema or format incompatibility - at the boundary between Service Inventory A and Service Inventory B (where XML Schema A must be converted to XML Schema B and vice versa), at Service B's write to Database A (where XML must be converted to CSV), and at Service D's write to Database B (where Inventory A's XML schema must be converted to the legacy proprietary XML schema). Options A and B are incorrect because they each address only a subset of the required transformation points - for example, applying transformation only at the inter-inventory boundary or only at the database boundaries - leaving at least one incompatibility unresolved. Option D is wrong because a valid solution does exist.
Memory tip: Think of the Data Model Transformation pattern as a "handshake adapter" - every time two components speak different data languages (different schemas OR different formats), an adapter must be inserted. Count the distinct incompatibilities in the scenario (here: 2 schema boundaries + 2 database format mismatches), and the correct answer is always the one that accounts for all of them.
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