For suppose I'm running a business named 'ALAM' which is wide spread across the globe.Now,I want to know how my business is running across the globe.I will ask a tech guy(oracle apps technical consultant) to develop a report.In that report I ask him to simply print the details of profit or loss,of every branch of my business across the world.He(tech guy) will come up with the report to me then I will come to know whether my company is running fine or not.Thereby, I can take necessary decisions to run my business fine.
Clearly we have seen that report will be developed by technical person,who must know the report building.
We build a report using sql,pl/sql.So,if your are strong in sql,pl/sql then its not a big deal to learn the report building.Its enough to learn the report developer tool.
As I said earlier I'm running a 'ALAM' business(which is factious).Suppose I'm using excel sheets to store the data.Now I want to install oracle apps(E-Business Suite) in my company. So,What ever data that is present in my excel sheets must also be present in my oracle apps tables(A table is a collection of rows and columns).Now I ask a tech guy to write a code such that my excel sheet data will get into oracle apps base tables.Then that tech guy will use 'conversion' to get the data from the legacy system(in our case it is excel sheet) into oracle apps base tables.
Interfaces are similar to conversions.Conversion is a one-time process where as Interface is on-going process every now and then.We run interfaces daily or periodically.
Interfaces are of two types
Inbound Interface:Transferring the data from the legacy system(in our case it is excel sheet) into the Oracle apps base tables.
Outbound Interface:Transferring the data from the Oracle apps base tables into the legacy system(It might be any of these SAP,People soft etc).
Extensions are nothing but personalizing the forms.In oracle e-business suite we have some where around 5000 to 6000 forms.In my 'ALAM' business i want to customise the po(purchase order) form of the oracle apps then i ask the tech guy to do that.He will use form builder tool to do that.