Variable/Dynamic based data sever connection in ODI topology

We can design Variable based connection in ODI Topology manager.

Why variable based connection...?

A. lets say user have requirement  to create some common components ( e.g. Knowledge modules) in ODI which can used across all the different products or projects.

B. Now different projects have different data severs & different data severs ( physical & logical) will be associated with different environments  like production, development.

C. Usually in Any software domain ( banking,automobile,retail etc) developers tries to develop a component which can be used across all the products/projects. 

Example:

 Lets assume source & target databases for 'n' number of projects & all products or projects have same type of  database tables DDL structure.

Source : Oracle & Target : Postgresql

so 'n' number of data base connections required in topology manager ? 

'n' number of interfaces or packages required to perform load to target ?

NO, just one connection (topology manager) & one package(designer) to perform load.

Create a metadata table 'Metadata' in oracle which will contain all the source & target database details like ( sever name,port,etc) & add one column for Primary Key ( numeric)  

Create variables such as, for source schema V_SRC_SCHEMA & V_SRC_database, V_SRC_port,etc & similarly for target V_target .
Create a variable for primary key column defined in metadata table & refresh all source & target variables on the basis of Primay Key. 

Create only one connection in topology manager for source & target with the variables created above & create variable based logical schema too...
Create Models with variable based logical schema
Now create a interface to load data from source to target

Finally put the variables ( Refresh Mode) & Interfaces in the final package & generate Scenario with variable parameter Primary key .

Now Scenario is ready for use, Just pass the of the primary key value of the connection sever ( defined in meta data table) to the scenario & DATA will be loaded from SOURCE --> TARGET for that product/project................

In next phase i will attach screenshot for this ............