The registration database contains the details and the applications that support various types of DDE/OLE Automation operations.
It is useful to appreciate the difference in structure between the WIN.INI file and the REG.DAT database. WIN.INI is simply a text document. There are no special structures other than headings (simply titles enclosed in brackets) that organize the information. If you want to locate an item in the WIN.INI file, you must search through the file for the specific item you want to locate. The registration database is a tree-like, structured database used for storing information relating to program and file operations, in particular, those that involve the use of DDE or OLE. The tree structure makes it easier to keep the complex set of instructions, needed to implement DDE and OLE operations, organized and accessible by the applications that need to use them. This is not possible when you are working with a text document like WIN.INI. The WIN.INI file records all sorts or information about the Windows system in a simple sequential listing.