COMPUTER APPLICATIONS 2 Marks Quetions

Primary key is used to uniquely identify the record in a database. It can be a column or a set of columns in the table. Main features of primary key are as follows:

1. It must contain a unique value for each record of table.
2. It does not contain null values.

A database contains multiple tables whereas, a table cannot exist outside a database.

Fields are one type of information. A record contains logically related fields. A table Emp name contains logically related records.

EmpNo	Name	Salary
1.	Shridhar	20000
2.	Raghav	40000

Here EmpNo, Name and Salary are three different fields. 1, Shridhar, 20000 represents one complete record.

Possible primary keys for an Employee table are empcode, empphonenumber.

DBMS is used to store data at a centralised location.
It is used to minimise data redundancy and data inconsistency.

AdmissionNo should be set as primary key because admission numbers are unique for each and every students of the school, which is not possible in the case with RollNo and Name.

In a database, a form is a window or a screen that contains numerous fields or spaces to enter data. Forms can be used to view and edit your data. It is an interface in user specified layout.
e.g. a user can create a data entry form that looks exactly like a paper form. People generally prefer to enter data into a well-designed form, rather than a table.

It is a collection of programs that enables users to create, maintain database and control all the access to the database. It is a computer based record keeping system. DBMS is a software package that manages database, e.g. MySQL, INGRES, MS-ACCESS etc.
DBMS is actually a tool that is used to perform any kind of operation on data in database.

A field which uniquely identifies each record in a table is known as primary key. e.g. empld is the primary key of the Employee table.

In a table, rows are called records and columns are termed as fields. A row stores complete information of a record whereas column stores only similar data values for all records

RDBMS is a type of DataBase Management System that stores data in the form of relations (tables). Relational databases are powerful, so they require few assumptions about how data is related or how, it will be extracted from the database.

When you want to print those records which are fetched from your database, design a report. It is an effective way to present data in a printed format. It allows you to represent data retrieved from one or more tables, so that it can be analysed.

A query is an inquiry into the database using the SELECT statement.These statements give you filtered data according to your conditions and specifications indicating the fields, records and summaries which a user wants to fetch from a database.

Can ensure data security.
Reduces the data redundancy.

High complexity
Database failure