Q1. Differentiate between Traditional File System & Modern Database System? Describe the properties of Database & the Advantage of Database?
Answer : Differentiate between Traditional File System & Modern Database System:
| Traditional File System | Modern Database Systems |
| Traditional File system is the system that was followed before the advent of DBMS i.e., it is the older way. | This is the Modern way which has replaced the older concept of File system. |
| In Traditional file processing, data definition is part of the application program and works with only specific application. |
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| File systems are Design Driven; they require design/coding change when new kind of data occurs.
E.g.:: In a traditional employee the master file has Emp_name, Emp_id, Emp_addr, Emp_design, Emp_dept, Emp_sal, if we want to insert one more column ‘Emp_Mob number’then it requires a complete restructuring of the file or redesign of the application code, even though basically all the data except that in one column is the same. |
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| Traditional File system keeps redundant [duplicate] information in many locations. This might result in the loss of Data Consistency.
For e.g.: Employee names might exist in separate files like Payroll Master File and also in Employee Benefit Master File etc. Now if an employee changes his or her last name, the name might be changed in the pay roll master file but not be changed in Employee Benefit Master File etc. This might result in the loss of Data Consistency. |
Redundancy is eliminated to the maximum extent in DBMS if properly defined. |
| In a File system data is scattered in various files, and each of these files may be in different formats, making it difficult to write new application programs to retrieve the appropriate
data. |
This problem is completely solved here. |
| Security features are to be coded in the Application Program itself. | Coding for security requirements is not
required as most of them have been taken care by the DBMS. |
Properties of Database:
The following are the important properties of Database:
1. A database is a logical collection of data having some implicit meaning. If the data are not related then it is not called as proper database.
E.g. Student studying in class II got 5th rank.
2. A database consists of both data as well as the description of the database structure and constraints.
3. A database can have any size and of various complexity. If we consider the above example of employee database the name and address of the employee may consists of very few records each with simple structure.
Like this there may be „n number of records.
4. The DBMS is considered as general-purpose software system that facilitates the process of defining, constructing and manipulating databases for various applications.
5. A database provides insulation between programs, data and data abstraction. Data abstraction is a feature that provides the integration of the data source of interest and helps to leverage the physical data however the structure is.
6. The data in the database is used by variety of users for variety of purposes. For E.g. when you consider a hospital database management system the view of usage of patient database is different from the same used by the doctor. In this case the data are stored separately for the different users. In fact it is stored in a single database. This property is nothing but multiple views of the database.
7. Multiple user DBMS must allow the data to be shared by multiple users simultaneously. For this purpose the DBMS includes concurrency control software to ensure that the updation done to the database by variety of users at single time must get updated correctly. This property explains the multiuser transaction processing.
Advantage of Database:
1. Redundancy is reduced
2. Data located on a server can be shared by clients
3. Integrity (accuracy) can be maintained
4. Security features protect the Data from unauthorized access
5. Modern DBMS support internet based application.
6. In DBMS the application program and structure of data are independent.
7. Consistency of Data is maintained
8. DBMS supports multiple views. As DBMS has many users, and each one of them might use it for different purposes, and may require to view and manipulate only on a portion of the database, depending on requirement.
Q2. What is the disadvantage of sequential file organization? How do you overcome it? What are the advantages & disadvantages of Dynamic Hashing?
Q3. What is relationship type? Explain the difference among a relationship instance, relationship type
& a relation set?
Q4. What is SQL? Discuss.
Q5. What is Normalization? Discuss various types of Normal Forms?
Q6. What do you mean by Shared Lock & Exclusive lock? Describe briefly two phase locking protocol?
