Subject : Database Management Systems
a. What are the advantages of DBMS over flat file system?
b. Define Data Models and explain with example.
c. Explain in detail Role of DBA
d. Write short notes on :
b. Data Independence
c. Weak Enti
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Basic PL/SQL Block Structure
PL/SQL is structured into blocks and can use conditional statements, loops and branches to control
program flow. Variables can be scoped so that they are only visible within the block where they are
CHAR (size) A fixed-sized field of characters. The largest this particular datatype can become is
2000 bytes. In other words, it can only hold 2000 characters. If you dont specify the length of the
CHAR datatype, the def
Case Study 1
A university database contains information about professors (identified by social
security number, or SSN) and courses (identified by course_id). Professors teach
courses; each of the following situations concerns the Teaches relationship set
How a Hard Disk Stores
The data stored in a hard disk will
not be erased when the computer is
When the CPU of a computer needs
to use information stored on the
1. What is database?
A database is a logically coherent collection of data with some inherent meaning,
representing some aspect of real world and which is designed, built and populated
with data for a specific purpose.
2. What is DBMS?
It is a collection
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Database Management System
Database is a collection of logically related data . It is not a random collection. It is
designed and populated for specific purpose.
It is a collection of programs which enable users to create and maintain d
Assumption: A customer can have multiple orders and an order can include multiple
CUSTOMER ORDER (CustName, Order No, Prod No, ProdDesc, Qty, Cust Address,
1NF - remove multi valued attributes
CUSTOMER (CustName, Cus
1. Which is the subset of SQL commands used to manipulate Oracle Database
structures, including tables?Data Definition Language (DDL)
2. What operator performs pattern matching?LIKE operator
4. What operator tests column for the absence of dataIS N
Creating our two example tables with constraints
Constraints are used to enforce table rules and prevent data dependent deletion (enforce database
integrity). You may also use them to enforce business rules (with some imagination).
Our two example tables