A database application is a software program, which is designed basically for entering and retrieving data from an electronic database and are broadly used. Databases form a basic part of almost all businesses today. For example, when using the internet to browse and get to an online shop to purchase a product you are accessing data stored in the database system. Another example is when you browse a bank’s website and retrieve your bank transaction and balance records you are doing that from the bank’s database system. Some representative applications are universities, telecommunication, airlines, banks etc.
For student records, course registrations, and grades. Also online courses and examination records are stored in a database.
These organization used database for keeping records of calls made, generating monthly bills, maintaining balances on prepaid calling cards and storing information about their communication networks.
Read: What Is Database?
For reservations, records of flight arrival and flight departure.
For keeping customer information, accounts, and loans, and every day’s banking transactions.
Is the ability to modify schema definition in one level without affecting schema definition in the next higher level. There are two types of data independence
Physical Data Independence and
Logical Data Independence
Physical data independence allows modification in the physical storage devices or organization of the files to be made without requiring changes in the conceptual view or any of the external views and hence in the application programs using the database.
Logical data independence implies that application programs need not be modify if fields are added to an existing record; nor do they have to be modify if fields not used by application programs are deleted. Logical data independence indicates that the conceptual schema can be modify without affecting the existing external schema.
The advantage of data independence in the database environment is that it allows modification at one level of the database, without affecting other levels. These modification are absorbed by the mappings between the levels.
Logical data independence is more difficult to achieve than physical independence. Since application programs are heavily dependent on the logical structure of the data they access.
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