The applications that constitute an enterprise's existing system for handling companywide information. These applications

provide an information infrastructure for an enterprise. An enterprise information system offers a well-defined set of

services to its clients. These services are exposed to clients as local or remote interfaces or both. Examples of enterprise

information systems include enterprise resource planning systems, mainframe transaction processing systems, and legacy  DATABASE system

Object Linking and Embedding (OLE) clipboard is a more capable clipboard than the windows traditional clipboard. To transfer a large image using a legacy clipboard one must allocate enough memory space to copy this image. However using the OLE clipboard you can transfer the bitmap in a more sensible medium like a file on a hard disk.OLE drag and drop is a visual method of transferring data. Unlike having separate commands like cut, copy and paste the OLE drag and drop lets you grab a piece of data with the mouse and drop it in the desired location.So to summarize it there are two broad differences between OLE and legacy clipboard. OLE clipboard is completely COM based and secondly it supports storage medium other than global memory.OLE drag and drop is programmatically very similar to OLE clipboard. The data provider or data source creates a data object that encapsulates the data and makes an IDataObject pointer available. The data consumer or drop target retrieves the IDataObject and uses it to extract data from the data object. The drop source initiates a drag and drop operation by passing an IDataObject pointer to ::DoDragDrop. Any window that is interested inbeing a drop target registers itself with the system by calling ::RegisterDragDrop. If drop occurs in a registered window then the drop target is handed the IDataObject pointer passed to ::DoDragDrop.

Enumeration and Iterator both are using looping statement.Enumeration is legacy class.iterator is cotains extra
method than Enumeration.
Enumeration is a read only interface, by using this we can loop thro' the elements only. But using iterator interface we can traverse and also remove the object.

Legacy classes are those that were built using Java 1.1 or Java 1.2 API. In general we cannot use this term for java classes. Say for example when Java 1.0 was available Vector was used instead of dynamic array and since there was no ArrayList class people were forced to use Vector for this purpose.
When Java 1.2 was released ArrayList was much more advanced to Vector but has all the features of Vector too.
So people started using ArrayList instead of Vector (this again depends on the project requirement, both Vector and ArrayList have their own advantages). And in this case Vector became legacy class
But this is not constant since in future Sun may introduce a new class that is much more advanced to ArrayList and Vector. And then we call both ArrayList and Vector as legacy classes.
But in general a "legacy" is a term used to define a software created using older version of software.

Data can be uploaded into a database table via the data dictonary or program. Witout using the data dictonary data can be put in the dbtab from a program using the update statement. Also the data can be transferred from the legacy system(non sap system) or external system into database table in sap using the BDC(batch data communication) concept.

LSMW is used for migrating data from a legacy system to SAP system, or from one SAP system to another.