Need for Multiple Access Paths
In practice, most of the online information systems need the support of multi-key files. For example, consider a banking database application having a lot of different kinds of users such as:
- Teller
- Loan officers
- Brach manager
- Account holders
All of these users access the bank data though in a diverse way. Let us suppose a sample data format for the Account relation in a bank as:
Account Relation:
|
Account
Number
|
Account
Holder Name
|
Branch
Code
|
Account type
|
Balance
|
Permissible
Loan Limit
|
|
|
|
|
|
|
|
A teller may access the record over to check the balance at the time of withdrawal. One needs to access the account on the basis of account number and branch code. A loan approver may be interested in searching the potential customer by accessing the records in declining order of permissible loan limits. A branch manager may need finding the top ten most preferred customers in each category of account so may access the database in the order of balance and account type. The account holder may be interested in his/her own record. Therefore, all these applications are trying to refer to the similar data but using dissimilar key values. Therefore, all the applications as above need the database file to be accessed in dissimilar order and format. What may be the most efficient way to give faster access to all such applications? Let us talk about two approaches for this:
- By Replicating Data
- By providing indexes.