Textbook: Introduction to Database and DBMS | Computer Science for Class 8 PDF Download

 Page 1


Moz: How will you extract the data that you require?
Jy oti:	Based	on	the	room	occupancy	details,	w e	can	find	if	rooms	are	av ailable	for	our	dates.
Moz: Yes, this process is called information extraction. It is also called querying the database. A 
Database Management System provides the software programs and tools to control the creation, 
maintenance and use of a database. 
Introduction to Database and DBMS 
9
A	 database	 is	 a	 collection	 of	 data	 that	 is	 organized	 for	 easy	 access,	 retrieval	 and	 management	
of	 its	 contents.	 A	 database	 has	 one	 or	 more	 related 	 tables	 of	 data.	 The	 data	 can	 be	 any	
format	like	text,	numeric,	images,	audio,	and	video.
Concept
Database
Informaton
Aim: In this lesson, you will learn:
- Database, tables, queries.
- Using	DBMS	tools	and	softw are.
- Applications of database.
Jy oti:	 W e	 are	 going	 to	 Kulu	 Manali	 for	 the	 holidays.	 W e	 are	 looking	 at	 the	 v arious	 places	 that	 w e	 can	
visit and which hotel has vacant rooms. 
T ejas:	 It	 is	 interesting	to	 know	 that	 the	 w ebsite	 provides	 room	 v acancy	 details	 along	 with	 dates.	 This	
information is also updated regularly! 
Moz: Yes. A database is used to store such data and a database management system is used to  
retrieve information.
Jy oti:	How	is	the	data	stored	in	the	database?
Moz: Data is stored in tables. These tables are organized in such a way that information required can 
be easily retrieved. For example, consider a hotel in Kulu Manali. You want to stay in this hotel. What 
is the information required by you to book a room in this hotel?
T ejas:	Room’ s	v acancy	status	for	some	particular	dates.	
Moz: What data would be required to find room vacancy information?
Jy oti:	W e	w ould	need	data	on:	(1)	Rooms	in	the	hotel	and	their	details,	(2)	Room	occupancy	details.
Moz: Right. You have defined two tables for a hotel database, one where room details are stored and 
the other where the room occupancy details are stored. 
Information
Information about 
the rooms available
Page 2


Moz: How will you extract the data that you require?
Jy oti:	Based	on	the	room	occupancy	details,	w e	can	find	if	rooms	are	av ailable	for	our	dates.
Moz: Yes, this process is called information extraction. It is also called querying the database. A 
Database Management System provides the software programs and tools to control the creation, 
maintenance and use of a database. 
Introduction to Database and DBMS 
9
A	 database	 is	 a	 collection	 of	 data	 that	 is	 organized	 for	 easy	 access,	 retrieval	 and	 management	
of	 its	 contents.	 A	 database	 has	 one	 or	 more	 related 	 tables	 of	 data.	 The	 data	 can	 be	 any	
format	like	text,	numeric,	images,	audio,	and	video.
Concept
Database
Informaton
Aim: In this lesson, you will learn:
- Database, tables, queries.
- Using	DBMS	tools	and	softw are.
- Applications of database.
Jy oti:	 W e	 are	 going	 to	 Kulu	 Manali	 for	 the	 holidays.	 W e	 are	 looking	 at	 the	 v arious	 places	 that	 w e	 can	
visit and which hotel has vacant rooms. 
T ejas:	 It	 is	 interesting	to	 know	 that	 the	 w ebsite	 provides	 room	 v acancy	 details	 along	 with	 dates.	 This	
information is also updated regularly! 
Moz: Yes. A database is used to store such data and a database management system is used to  
retrieve information.
Jy oti:	How	is	the	data	stored	in	the	database?
Moz: Data is stored in tables. These tables are organized in such a way that information required can 
be easily retrieved. For example, consider a hotel in Kulu Manali. You want to stay in this hotel. What 
is the information required by you to book a room in this hotel?
T ejas:	Room’ s	v acancy	status	for	some	particular	dates.	
Moz: What data would be required to find room vacancy information?
Jy oti:	W e	w ould	need	data	on:	(1)	Rooms	in	the	hotel	and	their	details,	(2)	Room	occupancy	details.
Moz: Right. You have defined two tables for a hotel database, one where room details are stored and 
the other where the room occupancy details are stored. 
Information
Information about 
the rooms available
T ejas:	What	does	control	mean	here?
Moz: In the hotel reservation database, room occupancy is entered by the hotel management.  
The management does not want anyone to access these tables and modify the data. So, they may 
restrict view of these data to selected users. There are inbuilt procedures in DBMS which make sure 
that such requirements are met. This is control of a database. 
Moz: Where else do you think DBMS are used?
Jy oti:	Railw ay	and	airline	ticket	booking.
T ejas:	In	our	school	to	maintain	the	records	of	students,	library .
Moz: Yes. Databases are used in many online applications.
Database	 management	 system	 (DBMS)	 is	 a	 software	 package	 that	 provides	 software	
programs		to	control	the	creation,	maintenance	and	use	of	a	database.
Concept
Database	management	system	(DBMS)
The	software	programs	in	a	DBMS	provide	tools	and	software	programs	as	follows:
Create	and	maintain	users	of	database	and	database	administrators. •	
Define	and	create	the	tables. •	
Enter,	update	and	maintain	data. •	
Retrieve	information	and	reporting	tools. •	
Some	 popula r	 DBMS	 packages	 are:	 Oracle,	 Microsoft	 Access,	 MySQL,	 PostgreSQL,	 Open	
Office	database.
Example	of	applications	where	database	is	used	are:
Railway	and	Airline:	For	schedules	and	reservation. •	
Banking:	 For	 customer	 information,	 accounts,	 loans,	 transactions	 like	 deposits	 and	 •	
withdrawal	of	money.
Universities	 and	 schools:	 Student	 and	 teacher	 information,	 issue	 of	 books	 in	 library,	 •	
office	for	financial	transactions	like	student	fee	collection	and	salary	of	teachers.
Telecommunication:	For	keeping	track	of	number	of	calls	made	and	preparing	bills. •	
Shops:	 For	 displaying	 prices	 and	 preparing	 bills,	 keeping	 track	 of	 inventory	 and	 fast	 •	
moving	goods.
Info Info
DBMS	tools	and	software
Database Applications
Moz:	 Now	 look	 at	 the	 following	 table	 which	 belongs	 to	 a	 school	 database.	 Note	 the	 technical	 terms	
that are used for each part of the table.
class_8_student_info  
Student_id Name Date of birth
12 Sweta S 23/01/97
34 T ejas 14/12/96
23 Jy oti 15/08/96
45 Gurmeet 25/03/97
67 Ali 01/01/97
195 Sw eta	G 16/11/96
Page 3


Moz: How will you extract the data that you require?
Jy oti:	Based	on	the	room	occupancy	details,	w e	can	find	if	rooms	are	av ailable	for	our	dates.
Moz: Yes, this process is called information extraction. It is also called querying the database. A 
Database Management System provides the software programs and tools to control the creation, 
maintenance and use of a database. 
Introduction to Database and DBMS 
9
A	 database	 is	 a	 collection	 of	 data	 that	 is	 organized	 for	 easy	 access,	 retrieval	 and	 management	
of	 its	 contents.	 A	 database	 has	 one	 or	 more	 related 	 tables	 of	 data.	 The	 data	 can	 be	 any	
format	like	text,	numeric,	images,	audio,	and	video.
Concept
Database
Informaton
Aim: In this lesson, you will learn:
- Database, tables, queries.
- Using	DBMS	tools	and	softw are.
- Applications of database.
Jy oti:	 W e	 are	 going	 to	 Kulu	 Manali	 for	 the	 holidays.	 W e	 are	 looking	 at	 the	 v arious	 places	 that	 w e	 can	
visit and which hotel has vacant rooms. 
T ejas:	 It	 is	 interesting	to	 know	 that	 the	 w ebsite	 provides	 room	 v acancy	 details	 along	 with	 dates.	 This	
information is also updated regularly! 
Moz: Yes. A database is used to store such data and a database management system is used to  
retrieve information.
Jy oti:	How	is	the	data	stored	in	the	database?
Moz: Data is stored in tables. These tables are organized in such a way that information required can 
be easily retrieved. For example, consider a hotel in Kulu Manali. You want to stay in this hotel. What 
is the information required by you to book a room in this hotel?
T ejas:	Room’ s	v acancy	status	for	some	particular	dates.	
Moz: What data would be required to find room vacancy information?
Jy oti:	W e	w ould	need	data	on:	(1)	Rooms	in	the	hotel	and	their	details,	(2)	Room	occupancy	details.
Moz: Right. You have defined two tables for a hotel database, one where room details are stored and 
the other where the room occupancy details are stored. 
Information
Information about 
the rooms available
T ejas:	What	does	control	mean	here?
Moz: In the hotel reservation database, room occupancy is entered by the hotel management.  
The management does not want anyone to access these tables and modify the data. So, they may 
restrict view of these data to selected users. There are inbuilt procedures in DBMS which make sure 
that such requirements are met. This is control of a database. 
Moz: Where else do you think DBMS are used?
Jy oti:	Railw ay	and	airline	ticket	booking.
T ejas:	In	our	school	to	maintain	the	records	of	students,	library .
Moz: Yes. Databases are used in many online applications.
Database	 management	 system	 (DBMS)	 is	 a	 software	 package	 that	 provides	 software	
programs		to	control	the	creation,	maintenance	and	use	of	a	database.
Concept
Database	management	system	(DBMS)
The	software	programs	in	a	DBMS	provide	tools	and	software	programs	as	follows:
Create	and	maintain	users	of	database	and	database	administrators. •	
Define	and	create	the	tables. •	
Enter,	update	and	maintain	data. •	
Retrieve	information	and	reporting	tools. •	
Some	 popula r	 DBMS	 packages	 are:	 Oracle,	 Microsoft	 Access,	 MySQL,	 PostgreSQL,	 Open	
Office	database.
Example	of	applications	where	database	is	used	are:
Railway	and	Airline:	For	schedules	and	reservation. •	
Banking:	 For	 customer	 information,	 accounts,	 loans,	 transactions	 like	 deposits	 and	 •	
withdrawal	of	money.
Universities	 and	 schools:	 Student	 and	 teacher	 information,	 issue	 of	 books	 in	 library,	 •	
office	for	financial	transactions	like	student	fee	collection	and	salary	of	teachers.
Telecommunication:	For	keeping	track	of	number	of	calls	made	and	preparing	bills. •	
Shops:	 For	 displaying	 prices	 and	 preparing	 bills,	 keeping	 track	 of	 inventory	 and	 fast	 •	
moving	goods.
Info Info
DBMS	tools	and	software
Database Applications
Moz:	 Now	 look	 at	 the	 following	 table	 which	 belongs	 to	 a	 school	 database.	 Note	 the	 technical	 terms	
that are used for each part of the table.
class_8_student_info  
Student_id Name Date of birth
12 Sweta S 23/01/97
34 T ejas 14/12/96
23 Jy oti 15/08/96
45 Gurmeet 25/03/97
67 Ali 01/01/97
195 Sw eta	G 16/11/96
Moz: Let us extract information from these two tables we have seen so far. How will you query the 
database to find names of students who scored 70 and above marks in English?
Jy oti:	 First	 find	 the	 roll	 numbers	 of	 students	 who	 scored	 70	 or	 more	 marks	 in	 English	 from	 the	 	
class_8_marks	 table.	 Then	 find	 their	 names	 from	 class_8_student_info	 table	 and	 display	 the	 list	 of	
these names. 
Students who scored more than 70 and above marks in English.
Moz: Here is another table showing the class and marks.
class_8_marks 
Student_id English Maths Science Social studies Second language (SL) Marks (SL)
34 70 76 63 54 French 89
23 58 92 78 65 Hindi 65
67 80 98 87 76 French 70
195 51 78 56 67 Marathi 73
45 48 52 65 56 French 62
12 73 88 75 77 Hindi 78
T ejas
Ali
Sweta S
Each	row	of	a	table	is	called	a	record.
Headings	of	columns	in	a	table	are	called	the	field	names.
Each	cell	in	a	table	is	called	the	field	and	contains	one	item	of	data	in	the	record.	
The	unique	column	which	uniquely	identifies	a	record	is	called	the	primary	key.
Info
Technical	terms	used	for	each	component	of	a	table	in	the	database.
Student_id Name Date of birth
12 Sweta S 23/01/97
Student_id Name Date of birth
12 Sweta S 23/01/97
Student_id Name Date of birth
12 Sweta S 23/01/97
Concept
Step	3:	 Specify	Primary	key
Primary key
A	primary	key	uniquely	identifies	a	record.	 •	
A	primary	key	does	not	allow	duplicate	values. •	
Record
Field	name
Cell
Primary key
Student_id Name Date of birth
12 Sweta S 23/01/97
Concept
Query
Extraction of information
A	 “query”	 is	 a	 special	 view	 of	 a	 table	 corresponding	 to	 some	 desired	 information	 to	 be	
extrated.	 A	 query	 can	 display	 chosen	 records	 or	 chosen	 fields	 within	 records.	 A	 query	 can	
apply	to	one	table	or	to	multiple	tables,	if	they	are	linked	by	common	data	fields.	
Page 4


Moz: How will you extract the data that you require?
Jy oti:	Based	on	the	room	occupancy	details,	w e	can	find	if	rooms	are	av ailable	for	our	dates.
Moz: Yes, this process is called information extraction. It is also called querying the database. A 
Database Management System provides the software programs and tools to control the creation, 
maintenance and use of a database. 
Introduction to Database and DBMS 
9
A	 database	 is	 a	 collection	 of	 data	 that	 is	 organized	 for	 easy	 access,	 retrieval	 and	 management	
of	 its	 contents.	 A	 database	 has	 one	 or	 more	 related 	 tables	 of	 data.	 The	 data	 can	 be	 any	
format	like	text,	numeric,	images,	audio,	and	video.
Concept
Database
Informaton
Aim: In this lesson, you will learn:
- Database, tables, queries.
- Using	DBMS	tools	and	softw are.
- Applications of database.
Jy oti:	 W e	 are	 going	 to	 Kulu	 Manali	 for	 the	 holidays.	 W e	 are	 looking	 at	 the	 v arious	 places	 that	 w e	 can	
visit and which hotel has vacant rooms. 
T ejas:	 It	 is	 interesting	to	 know	 that	 the	 w ebsite	 provides	 room	 v acancy	 details	 along	 with	 dates.	 This	
information is also updated regularly! 
Moz: Yes. A database is used to store such data and a database management system is used to  
retrieve information.
Jy oti:	How	is	the	data	stored	in	the	database?
Moz: Data is stored in tables. These tables are organized in such a way that information required can 
be easily retrieved. For example, consider a hotel in Kulu Manali. You want to stay in this hotel. What 
is the information required by you to book a room in this hotel?
T ejas:	Room’ s	v acancy	status	for	some	particular	dates.	
Moz: What data would be required to find room vacancy information?
Jy oti:	W e	w ould	need	data	on:	(1)	Rooms	in	the	hotel	and	their	details,	(2)	Room	occupancy	details.
Moz: Right. You have defined two tables for a hotel database, one where room details are stored and 
the other where the room occupancy details are stored. 
Information
Information about 
the rooms available
T ejas:	What	does	control	mean	here?
Moz: In the hotel reservation database, room occupancy is entered by the hotel management.  
The management does not want anyone to access these tables and modify the data. So, they may 
restrict view of these data to selected users. There are inbuilt procedures in DBMS which make sure 
that such requirements are met. This is control of a database. 
Moz: Where else do you think DBMS are used?
Jy oti:	Railw ay	and	airline	ticket	booking.
T ejas:	In	our	school	to	maintain	the	records	of	students,	library .
Moz: Yes. Databases are used in many online applications.
Database	 management	 system	 (DBMS)	 is	 a	 software	 package	 that	 provides	 software	
programs		to	control	the	creation,	maintenance	and	use	of	a	database.
Concept
Database	management	system	(DBMS)
The	software	programs	in	a	DBMS	provide	tools	and	software	programs	as	follows:
Create	and	maintain	users	of	database	and	database	administrators. •	
Define	and	create	the	tables. •	
Enter,	update	and	maintain	data. •	
Retrieve	information	and	reporting	tools. •	
Some	 popula r	 DBMS	 packages	 are:	 Oracle,	 Microsoft	 Access,	 MySQL,	 PostgreSQL,	 Open	
Office	database.
Example	of	applications	where	database	is	used	are:
Railway	and	Airline:	For	schedules	and	reservation. •	
Banking:	 For	 customer	 information,	 accounts,	 loans,	 transactions	 like	 deposits	 and	 •	
withdrawal	of	money.
Universities	 and	 schools:	 Student	 and	 teacher	 information,	 issue	 of	 books	 in	 library,	 •	
office	for	financial	transactions	like	student	fee	collection	and	salary	of	teachers.
Telecommunication:	For	keeping	track	of	number	of	calls	made	and	preparing	bills. •	
Shops:	 For	 displaying	 prices	 and	 preparing	 bills,	 keeping	 track	 of	 inventory	 and	 fast	 •	
moving	goods.
Info Info
DBMS	tools	and	software
Database Applications
Moz:	 Now	 look	 at	 the	 following	 table	 which	 belongs	 to	 a	 school	 database.	 Note	 the	 technical	 terms	
that are used for each part of the table.
class_8_student_info  
Student_id Name Date of birth
12 Sweta S 23/01/97
34 T ejas 14/12/96
23 Jy oti 15/08/96
45 Gurmeet 25/03/97
67 Ali 01/01/97
195 Sw eta	G 16/11/96
Moz: Let us extract information from these two tables we have seen so far. How will you query the 
database to find names of students who scored 70 and above marks in English?
Jy oti:	 First	 find	 the	 roll	 numbers	 of	 students	 who	 scored	 70	 or	 more	 marks	 in	 English	 from	 the	 	
class_8_marks	 table.	 Then	 find	 their	 names	 from	 class_8_student_info	 table	 and	 display	 the	 list	 of	
these names. 
Students who scored more than 70 and above marks in English.
Moz: Here is another table showing the class and marks.
class_8_marks 
Student_id English Maths Science Social studies Second language (SL) Marks (SL)
34 70 76 63 54 French 89
23 58 92 78 65 Hindi 65
67 80 98 87 76 French 70
195 51 78 56 67 Marathi 73
45 48 52 65 56 French 62
12 73 88 75 77 Hindi 78
T ejas
Ali
Sweta S
Each	row	of	a	table	is	called	a	record.
Headings	of	columns	in	a	table	are	called	the	field	names.
Each	cell	in	a	table	is	called	the	field	and	contains	one	item	of	data	in	the	record.	
The	unique	column	which	uniquely	identifies	a	record	is	called	the	primary	key.
Info
Technical	terms	used	for	each	component	of	a	table	in	the	database.
Student_id Name Date of birth
12 Sweta S 23/01/97
Student_id Name Date of birth
12 Sweta S 23/01/97
Student_id Name Date of birth
12 Sweta S 23/01/97
Concept
Step	3:	 Specify	Primary	key
Primary key
A	primary	key	uniquely	identifies	a	record.	 •	
A	primary	key	does	not	allow	duplicate	values. •	
Record
Field	name
Cell
Primary key
Student_id Name Date of birth
12 Sweta S 23/01/97
Concept
Query
Extraction of information
A	 “query”	 is	 a	 special	 view	 of	 a	 table	 corresponding	 to	 some	 desired	 information	 to	 be	
extrated.	 A	 query	 can	 display	 chosen	 records	 or	 chosen	 fields	 within	 records.	 A	 query	 can	
apply	to	one	table	or	to	multiple	tables,	if	they	are	linked	by	common	data	fields.	
Moz:	Good.	How	do	y ou	find	the	av erage	age	of	students	in	the	class?
T ejas:	 W e	 can	 find	 the	 age	 from	 the	 date	 of	 birth	 of	 students	 in	 the	 student_info	 table	 and	 calculate	 the	
average age. Here we are using only one table. 
Moz: Right. This is how database querying works. Let us do this practically using a database application 
provided by Openoffice. Let us take the example of your school data to understand database creation 
and information extraction. 
Start Open office database: Openoffice        OpenOffice.org database i. 
The Database Wizard helps you to create a database file and to register a new database within  ii. 
 OpenOffice.org.
 Creation of a database
Skill
Step	1:	Creating	a	new	database.
Select	 Create	 a	 new	 database	 and	 
click	on	next.
Step	2:	Registering	a	database.
Save	 and	 proceed	 with	 default	 settings	 and	 
click	Finish.	
2
Step	3:	Naming	a	database.
Give	an	appropriate	name	(ex:	cm8_db)	to	the	database	and	click	on	Save.	
3
1
 Creation of a table
Open the database file (cm8.odb). Click the Tables icon. Choose Create Table in Design View to  i. 
 create a new table.
Using this option you can create tables by defining the fields of the table required  ii. 
 by your application.
Page 5


Moz: How will you extract the data that you require?
Jy oti:	Based	on	the	room	occupancy	details,	w e	can	find	if	rooms	are	av ailable	for	our	dates.
Moz: Yes, this process is called information extraction. It is also called querying the database. A 
Database Management System provides the software programs and tools to control the creation, 
maintenance and use of a database. 
Introduction to Database and DBMS 
9
A	 database	 is	 a	 collection	 of	 data	 that	 is	 organized	 for	 easy	 access,	 retrieval	 and	 management	
of	 its	 contents.	 A	 database	 has	 one	 or	 more	 related 	 tables	 of	 data.	 The	 data	 can	 be	 any	
format	like	text,	numeric,	images,	audio,	and	video.
Concept
Database
Informaton
Aim: In this lesson, you will learn:
- Database, tables, queries.
- Using	DBMS	tools	and	softw are.
- Applications of database.
Jy oti:	 W e	 are	 going	 to	 Kulu	 Manali	 for	 the	 holidays.	 W e	 are	 looking	 at	 the	 v arious	 places	 that	 w e	 can	
visit and which hotel has vacant rooms. 
T ejas:	 It	 is	 interesting	to	 know	 that	 the	 w ebsite	 provides	 room	 v acancy	 details	 along	 with	 dates.	 This	
information is also updated regularly! 
Moz: Yes. A database is used to store such data and a database management system is used to  
retrieve information.
Jy oti:	How	is	the	data	stored	in	the	database?
Moz: Data is stored in tables. These tables are organized in such a way that information required can 
be easily retrieved. For example, consider a hotel in Kulu Manali. You want to stay in this hotel. What 
is the information required by you to book a room in this hotel?
T ejas:	Room’ s	v acancy	status	for	some	particular	dates.	
Moz: What data would be required to find room vacancy information?
Jy oti:	W e	w ould	need	data	on:	(1)	Rooms	in	the	hotel	and	their	details,	(2)	Room	occupancy	details.
Moz: Right. You have defined two tables for a hotel database, one where room details are stored and 
the other where the room occupancy details are stored. 
Information
Information about 
the rooms available
T ejas:	What	does	control	mean	here?
Moz: In the hotel reservation database, room occupancy is entered by the hotel management.  
The management does not want anyone to access these tables and modify the data. So, they may 
restrict view of these data to selected users. There are inbuilt procedures in DBMS which make sure 
that such requirements are met. This is control of a database. 
Moz: Where else do you think DBMS are used?
Jy oti:	Railw ay	and	airline	ticket	booking.
T ejas:	In	our	school	to	maintain	the	records	of	students,	library .
Moz: Yes. Databases are used in many online applications.
Database	 management	 system	 (DBMS)	 is	 a	 software	 package	 that	 provides	 software	
programs		to	control	the	creation,	maintenance	and	use	of	a	database.
Concept
Database	management	system	(DBMS)
The	software	programs	in	a	DBMS	provide	tools	and	software	programs	as	follows:
Create	and	maintain	users	of	database	and	database	administrators. •	
Define	and	create	the	tables. •	
Enter,	update	and	maintain	data. •	
Retrieve	information	and	reporting	tools. •	
Some	 popula r	 DBMS	 packages	 are:	 Oracle,	 Microsoft	 Access,	 MySQL,	 PostgreSQL,	 Open	
Office	database.
Example	of	applications	where	database	is	used	are:
Railway	and	Airline:	For	schedules	and	reservation. •	
Banking:	 For	 customer	 information,	 accounts,	 loans,	 transactions	 like	 deposits	 and	 •	
withdrawal	of	money.
Universities	 and	 schools:	 Student	 and	 teacher	 information,	 issue	 of	 books	 in	 library,	 •	
office	for	financial	transactions	like	student	fee	collection	and	salary	of	teachers.
Telecommunication:	For	keeping	track	of	number	of	calls	made	and	preparing	bills. •	
Shops:	 For	 displaying	 prices	 and	 preparing	 bills,	 keeping	 track	 of	 inventory	 and	 fast	 •	
moving	goods.
Info Info
DBMS	tools	and	software
Database Applications
Moz:	 Now	 look	 at	 the	 following	 table	 which	 belongs	 to	 a	 school	 database.	 Note	 the	 technical	 terms	
that are used for each part of the table.
class_8_student_info  
Student_id Name Date of birth
12 Sweta S 23/01/97
34 T ejas 14/12/96
23 Jy oti 15/08/96
45 Gurmeet 25/03/97
67 Ali 01/01/97
195 Sw eta	G 16/11/96
Moz: Let us extract information from these two tables we have seen so far. How will you query the 
database to find names of students who scored 70 and above marks in English?
Jy oti:	 First	 find	 the	 roll	 numbers	 of	 students	 who	 scored	 70	 or	 more	 marks	 in	 English	 from	 the	 	
class_8_marks	 table.	 Then	 find	 their	 names	 from	 class_8_student_info	 table	 and	 display	 the	 list	 of	
these names. 
Students who scored more than 70 and above marks in English.
Moz: Here is another table showing the class and marks.
class_8_marks 
Student_id English Maths Science Social studies Second language (SL) Marks (SL)
34 70 76 63 54 French 89
23 58 92 78 65 Hindi 65
67 80 98 87 76 French 70
195 51 78 56 67 Marathi 73
45 48 52 65 56 French 62
12 73 88 75 77 Hindi 78
T ejas
Ali
Sweta S
Each	row	of	a	table	is	called	a	record.
Headings	of	columns	in	a	table	are	called	the	field	names.
Each	cell	in	a	table	is	called	the	field	and	contains	one	item	of	data	in	the	record.	
The	unique	column	which	uniquely	identifies	a	record	is	called	the	primary	key.
Info
Technical	terms	used	for	each	component	of	a	table	in	the	database.
Student_id Name Date of birth
12 Sweta S 23/01/97
Student_id Name Date of birth
12 Sweta S 23/01/97
Student_id Name Date of birth
12 Sweta S 23/01/97
Concept
Step	3:	 Specify	Primary	key
Primary key
A	primary	key	uniquely	identifies	a	record.	 •	
A	primary	key	does	not	allow	duplicate	values. •	
Record
Field	name
Cell
Primary key
Student_id Name Date of birth
12 Sweta S 23/01/97
Concept
Query
Extraction of information
A	 “query”	 is	 a	 special	 view	 of	 a	 table	 corresponding	 to	 some	 desired	 information	 to	 be	
extrated.	 A	 query	 can	 display	 chosen	 records	 or	 chosen	 fields	 within	 records.	 A	 query	 can	
apply	to	one	table	or	to	multiple	tables,	if	they	are	linked	by	common	data	fields.	
Moz:	Good.	How	do	y ou	find	the	av erage	age	of	students	in	the	class?
T ejas:	 W e	 can	 find	 the	 age	 from	 the	 date	 of	 birth	 of	 students	 in	 the	 student_info	 table	 and	 calculate	 the	
average age. Here we are using only one table. 
Moz: Right. This is how database querying works. Let us do this practically using a database application 
provided by Openoffice. Let us take the example of your school data to understand database creation 
and information extraction. 
Start Open office database: Openoffice        OpenOffice.org database i. 
The Database Wizard helps you to create a database file and to register a new database within  ii. 
 OpenOffice.org.
 Creation of a database
Skill
Step	1:	Creating	a	new	database.
Select	 Create	 a	 new	 database	 and	 
click	on	next.
Step	2:	Registering	a	database.
Save	 and	 proceed	 with	 default	 settings	 and	 
click	Finish.	
2
Step	3:	Naming	a	database.
Give	an	appropriate	name	(ex:	cm8_db)	to	the	database	and	click	on	Save.	
3
1
 Creation of a table
Open the database file (cm8.odb). Click the Tables icon. Choose Create Table in Design View to  i. 
 create a new table.
Using this option you can create tables by defining the fields of the table required  ii. 
 by your application.
Step	1:	Create	table	using	design	view.
Step	2:	Table	field	names	with	datatype	
definition:
Enter	 new	 fields	 in	 rows	 from	 top	 to	 bottom.	 •	
Click	 the	 Field	 Name	 cell	 and	 enter	 a	 field	
name	for	each	data	field.
In	 the	 next	 cell	 to	 the	 right,	 define	 the	 Field	 •	
Type.	 When	 you	 click	 in	 the	 cell,	 you	 can	
select	a	field	type	in	the	drop-down	menu.
Step	3:	Select	a	primary	key: 
Step	4:	All	fields	and	data	types	defined
You	 can	 enter	 an	 optional	 Description	 for	 each	 field.	 The	 text	 of	 the	 description	 will	 appear	
as	a	tip	on	the	column	headings	in	the	table	view.
Step	5:	Field	properties
Field	 properties	 specify	 the	 data	 entry	 rules.	
Help	 is	 provided	 in	 the	 right	 most	 column.	
You	can	leave	as	default	for	now.
Step	 6:	 Give	 a	 name	 to	 the	 table	 and	
Save.
Example
Student_id	 uniquely	 identifies	 a	 student.	 Right-click	 the	 first	 column,	 and	 choose	 •	
Primary	 Key	 from	 the	 context	 menu.	 Note	 that,	 to	 edit	 the	 table	 contents	 a	 primary	 key	 has	 
to	be	specified.
 Specify Primary key
Skill
1
2
3
4
1
2
3
5
6
See	Example	below. •