For ABAPers Difference between LSMW and BDC

What is the exact difference between BDC and LSMW?
BDC is the way to transfer data by writing a batch input program which can use either session or call transaction method.
LSMW used to transfer data without/less code.
What type of data we transfer using LSMW?
LSMW is best suited for transferring master data.
Actually BDC and LSMW are not comparable at all.
for example LSMW itself can use BDC as a way of mass data transfer.
BDC is a mass data transfer technique via screen logic of existing SAP Data entry transactions. It behaves as if you are manually making thousand of entires into sap system as a background job. And that is probably the reason why BAPI's are preffered over BDC's.
On the other hand LSMW is a tool to facilitate DATA migration from other legacy systems ... It contains step by step procedure for data migration.
Like Managing Data Migration Projects , Creating Source Structures , Mapping Source structures wid Target structures , etc etc
LSMW internally might well be using the following techniqes for data transfer..1. IDOX2. Direct Input / BDC4. BAPI's
LSMW is an encapsulated data transfer tool. It can provide the same functionality as BDC infact much more but when coming to techinical perspective most the parameters are encapulated. To listout some of the differences :
LSMW is basicaly designed for a fuctional consultant who do not do much coding but need to explore the fuctionality while BDC is designed for a technical consultant.
LSMW offers different techinque for migrating data: Direct input ,BAPI,Idoc,Batch input recording. While bdc basically uses recording.
LSMW mapping is done by SAP while in BDC we have to do it explicitly .
LSMW is basically for standard SAP application while bdc basically for customized application.
Coding can be done flexibly in BDC when compared to LSMW
Diff. between BDC and LSMW."The Data Transfer Workbench (or DX Workbench, transaction SXDA) is an integrated SAP tool that supports data transfer and analysis. It does not have the built-in features for mapping for source structures to target structures, but it will allow you to integrate Legacy System Migration Workbench (LSMW) objects as processing tasks within a run definition. The DX workbench has many features for creating test data and performing data migrations - for example, logging of data migration runs. However, if you need to map or convert data, you should use the LSMW. Or, you can integrate your LSMW objects as task within a more user-friendly data migration run, in which the LSMW project steps "Read data", "Convert data," and "Start IDoc processing" are automated and use the features of both tools. If you donot need logging and automated data migration runs, you can perform your data migration without the DX Workbench."
釘atch Data Communication (BDC) is the oldest batch interfacing technique that SAP provided since the early versions of R/3. BDC is not a typical integration tool, in the sense that, it can be only be used for uploading data into R/3 and so it is not bi-directional. BDC works on the principle of simulating user input for transactional screen, via an ABAP program. Typically the input comes in the form of a flat file. The ABAP program reads this file and formats the input data screen by screen into an internal table (BDCDATA). The transaction is then started using this internal table as the input and executed in the background.
In 舛all Transaction・ the transactions are triggered at the time of processing itself and so the ABAP program must do the error handling. It can also be used for real-time interfaces and custom error handling & logging features. Whereas in Batch Input Sessions, the ABAP program creates a session with all the transactional data, and this session can be viewed, scheduled and processed (using Transaction SM35) at a later time. The latter technique has a built-in error processing mechanism too.
Batch Input (BI) programs still use the classical BDC approach but doesn稚 require an ABAP program to be written to format the BDCDATA. The user has to format the data using predefined structures and store it in a flat file. The BI program then reads this and invokes the transaction mentioned in the header record of the file.
Direct Input (DI) programs work exactly similar to BI programs. But the only difference is, instead of processing screens they validate fields and directly load the data into tables using standard function modules. For this reason, DI programs are much faster (RMDATIND - Material Master DI program works at least 5 times faster) than the BDC counterpart and so ideally suited for loading large volume data. DI programs are not available for all application areas.