Chapter 3 Database Concepts Solutions
Question - 11 : - Write the significance of a foreign key.
Answer - 11 : - A foreign key is used to Establish relationship between any two tables of RDBMS.
Question - 12 : - What are the main purposes of a database system?
Answer - 12 : -
- Storage of information.
- Retrieval of information quickly.
- Sorting, selecting data that satisfies certain criteria (filtering).
- Produce the report in some standardised and readable format.
Question - 13 : - What is the difference between тАШRowsтАЩ and тАШColumnsтАЩ in a table?
Answer - 13 : - 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.
Question - 14 : - Define query in the context of database.
Answer - 14 : - 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.
Question - 15 : - Define forms and what is the need of using them?
Answer - 15 : -
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.
Question - 16 : - What do you understand by report?
Answer - 16 : - 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.
Question - 17 : - What do you mean by DBMS?
Answer - 17 : -
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.
Question - 18 : - Define RDBMS.
Answer - 18 : - 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.
Question - 19 : - What is the utility of primary key in database? Write distinct features of primary keys.
Answer - 19 : -
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:
- It must contain a unique value for each record of table.
- It does not contain null values.
Answer - 20 : -
A database consists of several components. Each component plays an important role in the database system environment.
The major components of database are as follows:
Data
It is raw numbers, characters or facts represented by value. Most of the organisations generate, store and process large amount of data. The data acts as a bridge between the hardware and the software. Data may be of different types such as User data, Metadata and Application Metadata.
Software
It is a set of programs that lies between the stored data and the users of database. It is used to control and manage the overall computerised database. It uses different types of software such as MySQL, Oracle etc.
Hardware
It is the physical aspect of computer, telecommunication and database, which consists of the secondary storage devices such as magnetic disks, optical discs etc., on which data is stored.
Users
It is the person, who needs information from the database to carry out its primary business responsibilities.
The various types of users which can access the database system are as follows:
Database Administrator (DBA)
A person, who is responsible for managing or establishing policies for the maintenance and handling the overall database management system is called DBA.
Application Programmers
The people, who write application programs in programming languages to interact and manipulate the database are called application programmers.
End-user
A person, who interacts with the database system to perform different operations on the database like inserting, deleting etc., through menus or forms.