Hi Nilima,
At an abstract level,
BDC - to transfer DATA from non-sap or sap systems to a sap system.
LSMW - to transfer DATA from non-sap to sap system ..( more user friendly as this tool is embedded into R/3 system)
where as,
EDI - to exchange BUSINESS DATA across the systems ( sap to non sap or between sap systems of different Business partners)
ALE - similar to EDI technology but its developed by SAP, where as EDI which is a third party tool.
Pls try to understand the difference between DATA and BUSINESS DATA in the above scenario.
DATA - normal data which is stored in notepad or excel sheet.
BUSINESS DATA - includes SAP deployed docs like sales order document, Billing document etc..
that is the reason why we use IDOCs( in ALE and EDI) to exchange such high-end data.
Hope this helps.!!
Thanks,
Shiva Sai