Wednesday, December 7, 2016
Most of the
implementations I have seen do not give an optimal name to the context.
Yes the default
context id GLOBAL and you might think what's wrong with it?
There is
nothing wrong with it. If all you have is one set source and target. Dev source database loads to Dev Target database. For production I recommend having only one
context and it being GLOBAL.
In DEV, we can start
with one context, when we are loading from one dev source to one target. As
time moves on, you might have received a request to load from hotfix environment which contains a data which is not present in dev source database. I have seen couple of things
happen in this instance to load data from new data source.
- We change the existing data server connection details to point to new source - Very simple (Good for one time)
- Create new data source and update the logical and physical mapping (on GLOBAL context which have to be reverted again)
For onetime events,
both approaches are ok. Slowly you start getting requests to load from the new
data source again and again, and you find yourself repeating these procedures
over and over.
My recommendation in
this instance would be to create a new context named a follows
HOTFIX_DEV
<SRC>_<TARGET>
<SRC> -->
Source data source code where you are loading from
<TARGET>
--> Target data source code where you are loading to
Data source code can
be any text which can help you identify that group of data sources.
When you name the
contexts in the above mentioned manner and you perform the logical and physical
mapping accordingly, you have couple of advantages.
- You can react to requests for loading from multiple instances of sources instantaneously without scope for error
- You have an history of what loads have been performed from what sources. E.g. your testing team might come and hey, when are full load done from this data source. You can preserve the history to answer these questions based on context.
Ideal scenario might
be to have one source per one target but we all know that we are living far
from ideal world and this might make your life a little easier to deal with.
