Databases Reference
In-Depth Information
In some ways, you may want to consider how significant a major change is. For
example, the change might impact one operation out of ten. Do you really want
your clients to have to reimplement every call to every single operation because
one operation (which they might not be using) has changed?
WSDL versioning
When we modify our WSDL contract, we again follow the same core principles for
major and minor versions that we outlined previously. From a service perspective, a
minor change includes:
•
Addition of an operation: This merely extends the WSDL and thus on its own
is backwards compatible
Addition of a new optional parameter within the element wrapper used by
an input message
Making existing mandatory parameters within the element wrapper optional
for input messages
•
•
While major changes would include:
•
•
Deletion or renaming of an operation
Changes to the input and output parameters of an operation that don't
fall under the category of a minor change, that is, adding a new parameter
whether optional or mandatory to the response wrapper
Incorporating changes to the canonical model
If we upgrade our service to use a new minor version of the canonical model, then
our initial reaction might be that this only results in a minor change to the service,
as our new version will still be able to process all requests from consumers using a
service definition, based on an earlier version of the schema.
While this is true, the response generated by our service may no longer be
compatible with an earlier version of the schema. So, the consumer may not be able
to successfully process the response. In this scenario, you need to create a new major
version of the service.
Changes to the physical contract
From a versioning perspective, we don't generally consider changes to either the
<binding>
or
<service>
element. With regards to the
<binding>
element, we find it
helpful to consider it as part of the service implementation and thus follow the same
guidelines discussed earlier to decide whether it warrants a new version of a service.
