Database Reference
In-Depth Information
has its own limits, and these limits will be thoroughly tested during the unit stress test and
properly documented in the individual service profile.
The quantification of this principle is roughly similar to the measure of flexibility of hub-
and-spoke integration platform. For hub-and-spoke, with all enterprise applications con-
nected to it, you have the canonical data models for all entities presented by the applica-
tion. When a new application with its own data representation arrives, all that you need is
to perform the following:
• Transform the newly received application data model to a canonical model
• Establish routing rules for message flows in a hub for this application
For simplicity, we assume that a unified canonical protocol is in place. With this simplistic
model, we can estimate that a new XSLT (actually, two of them) with a reasonable level
of complexity could be built in four hours, and the routing rules in a static table can be
maintained in another two. Allocate a day for testing and we are ready for production in
less than 16 business hours! Theoretically. Let's now recall how reality typically bends our
plans.
What it
means
No.
How do we see it
Discoverability
and Abstrac-
tion
Yes, it's not a problem to build XSLT or XQuery in four hours. Obtaining the mapping instruction and understanding
the meaning of field names and data types can take week(s).
1
Standardized
contract
2
Not all data elements needed for CDM and other applications in the farm are available via a public API.
Loose Coup-
ling
3
To extract necessary data, we have to bypass the API and reach out for internal resources.
The extraction of additional data inevitably implements call-back interchange patterns, which are not always positive.
This could disrupt performance of the main app functions and put some logic outside the app boundaries.
4
Autonomy
Quite often, internal logic of a new application is more complex than what a simple request-response interchange pat-
tern can provide, thus requiring the hub
atomic transaction coordinator's
(
ATCs
) capabilities. We have to put more
logic on the hub.
Loose Coup-
ling
5
This shortlist of five items is only the tip of the iceberg; usually, it's more than a page
long. The bottom line is that the total time required for making a new application compos-
able via the hub-and-spoke approach is usually from two to six months.
Search WWH ::
Custom Search