Class 10 Info Tech Unit 3 RDBMS Session 1 Appreciate Concept of Database Management System 50+ Question Answer

Session 1 – Appreciate Concept of Database Management System – 50+ Question Answer

38. Differentiate between Primary Key and Foreign Key.

Answer:

Primary key	Foreign Key
Primary keys allow to uniquely identify all table records.	A foreign key in a relational database provides an association between data in two tables. i.e use to establish a relationship.
A table has only one primary key.	A table can have multiple foreign keys.

39. How primary key helps to search a record fast?

Answer: In Database, Primary Keys are indexed, which makes it faster for the database to search a record.

40. A table named School (containing data of students of the whole school) is created where each record consists of several fields including AdmissionNo (Admission Number), RollNO (Roll Number), and Name. Which field out of these three should be set as the primary key and why?

Answer: The AdmissionNo of table Student can be set as the Primary key.

Reason: The value of RollNo column is unique for class only not for school, while the value of AdmissionNo is unique for the whole school. With the help of AdmissionNo, it is easy to uniquely identify the records in school.

41. What is the need for a database?

Answer: A database refers to a collection of related data and a database system is basically a computer-based record-keeping system.

It manages the information about one particular enterprise and helps in taking decision. It facilitates the retrieval of information whenever required.

42. Write the relationship between a database and a table?

Answer: A database is the collection of several tables related to the organization, while a table is the collection of interrelated records.

43. How foreign key related to the primary key?

Answer: The value of a foreign key is derived from the domain of the primary key. The foreign key is used to relate two tables with the help of the primary key of other tables.

44. What is the difference between ‘Rows’ and ‘Columns’ in a table?

Answer: Rows are the collection of logically related columns i.e. representing one complete piece of information. While columns refer to one type of information.

In the above table, OrderId, CustomerName are the columns, while Complete information about orderid – 00789 refers to rows.

45. What is Query?

Answer: A Query is a statement that gives you filtered data according to your conditions and specifications.

46. What is Form?

Answer: A form is an interface in a user-specified layout, that lets users view, enter, and change data directly in the table.

47. What is Report?

Answer: A Report is an effective way to present data in a printed format. It is a formal, presentable printed document that lists data in a formatted manner.

48. Amrit is working for a nationalized bank and is in the process of creating a table to store the details of customers of the bank. Find out which of the following Fields of the table Bank can be selected as Primary Key, Candidate Key, and Alternate Key.

AccountNo	CustomerName	Dateofbirth	PANNumber	OpeningBalance

Answer: Primary Key : AccountNo,

Candidate Key : AccountNo and PANNumber,

Alternate Key : PANNumber

Direction: Answer Questions Number 49 to 53 on the basis of the given table named – Membership.

Name	MemberNumber	Instrument
Hassini	2015	Guitar
Milan	0365	Saxophone
Palash	0112	Clarinet
Afzal	8231	Piano
Jugal	0112	Clarinet

Table – Membership

49. How many records (cardinality) are there in table Membership?

Answer: 5 [Number of Rows is known as Cardinality]

50. How many fields (degree of the table) are there in table Membership?

Answer: 3 [Number of fields is known as Degree of table]

51. Is there any discrepancy in table Membership, as you can see MemberNumber 0112 is used twice? Why?

Answer: MemberNumber is a Primary Key in table MemberShip. We can not use the same value as MemberNumber for two or more records. Primary Key is always unique. This is the discrepancy.

52. Write down a valid MemberNumber for Jugal in table Membership?

Answer: Any unique number (like 0458) can be given. Must not exist in table Membership.

53. Can we use the ‘Name’ column of table Membership as the Primary Key? If No, then why?

Answer: No.

As you can see there is no duplicate value in the ‘Name’ column currently. So you can think Yes for Primary Key.

But when the size of the table increased, you can’t guarantee the same. That’s why we can’t use the column ‘Name’ as the Primary Key.