Data file: – Visual basic provide facility to handle data file for the application. The data file is separate from the application. When user call data file for application, it links with the proper application to manipulate the data.
Visual basic support two different types of data file, called Sequential data file and Random data file. A sequentially data file access sequentially one after other and from the first record every time but a random data file can access randomly and without any sequence. Any one record from beginning to end can be access at a time. A sequentially data file can be access only in a proper mode means if it is opened for input mode, it can be collect or retrieve data from that file and if it is opened in output mode, the data file used for only writing purpose. But a random data file provides all the three facilities such as for input only, for output only and for both input-output access speed of random data file is faster than that of a sequential data file because a sequential data file access in a sequence from beginning to end and a random data file access without any sequence or randomly. A major drawback in a random data file that its record size must be constant from beginning to end as well as its field size but it is not important or necessary for sequential data file.