Unit 3 – Relational Database Management Systems (Basic)
Class 10 Info Tech 402 NCERT Book exercise Solution
SESSION 3: PERFORM OPERATIONS ON TABLE
ASSESSMENT
Fill in the blanks:
1. The types of languages used for creating and manipulating the data in the Database are DDL & DML.
2. A Queries is a standard for commands that define the different structures in a database.
3. A DML is a language that enables users to access and manipulate data in a database.
4. A SELECT is a part of DML involving information retrieval only.
5. A popular data manipulation language is DML.
6. Tables are the basic building blocks of a database.
7. There are 3 types of Relationships in a table.
Short Answer Questions:
1. What is the file extension for databases created using OpenOffice.Org Base?
Answer: .odb (dot odb)
2. List any three file formats that can be managed using OpenOffice.Org Base?
Answer: .odf, .odb, .ods, .dbf, .csv, .xls, .accdb
3. How many types of relationships can be created in Base? Explain each of the them.
Answer: A relationship refers to an association or connection between two or more tables. When you relate two tables, you don’t need to enter the same data in separate tables.
There are three types of relationships which can be created in tables:
- ONE to ONE
- ONE to MANY OR MANY to ONE
- MANY to MANY
One to One Relationship : In this relationship, both the tables must have primary key columns.
One to Many Relationship : In this relationship, one of the table must have primary key column. It signifies that one column of primary key table is associated with all the columns of associated table.
Many to Many Relationship : In this relationship, no table has the primary key column. It signifies that all the columns of primary key table are associated with all the columns of associated table.
4. What do you mean by Sorting? In how many ways it can be done?
Answer: Sorting means to arrange the data in either ascending order of descending order. Select the column(s) then click on sort buttons. The data will be displayed accordingly.
Sorting can be done in two ways:-
(a) Sort Ascending and (ii) Sort Descending
5. Explain Referential Integrity with the help of an example.
Answer: Referential integrity is used to maintain accuracy and consistency of data in a relationship. In Base, data can be linked between two or more tables with the help of primary key and foreign key constraints.
Referential integrity helps to avoid:
(a) Adding records to a related table if there is no associated record available in the primary key table.
(b) Changing values in a primary if any dependent records are present in associated table(s).
(c) Deleting records from a primary key table if there are any matching related records available in associated table(s).
Unit 3 – Relational Database Management Systems (Basic)
Class 10 Info Tech 402 NCERT Book exercise Solution
SESSION 4: RETRIEVE DATA USING QUERY
ASSESSMENT
Fill in the blanks.
1. A FORM helps the user to systematically store information in the database.
2. A FORM enables users to view, enter, and change data directly in database objects such as tables.
3. SELECT statement retrieves zero or more rows from one or more database tables or database views.
4. By default, data is arranged in ascending order using ORDER BY clause.
5. UPDATE statement is used for modifying records in a database.
6. DELETE statement is used to remove one or more records in a Database.
Short Answer Questions:
1. Name DML commands.
Answer: DML stands for Data Manipulation Language.
There are four DML commands are :
SELECT, INSERT INTO, UPDATE, DELETE
2. What is the purpose of using queries?
Answer: Queries are commands that are used to define the data structure and also to manipulate the data in the database. Queries are use to retrieve the rows from database tables or database views.
3. Which clause of Select statement helps to display specific data?
Answer: WHERE clause is used to display specific data.
4. Differentiate between Where and Order by clause of SQL statements.
Answer: Where clause is use to select specific rows in query while Order By clause is use to arrange the result in specific order either in ascending or descending.
5. State the purpose of Update Command with the help of an example.
Answer: UPDATE command of SQL is used for modifying records in a database.
The general syntax of the update statement is as follows:
UPDATE tablename SET column_name = value [, column_name = value …]
[WHERE condition];
For example:
UPDATE employee SET salary = 25000 WHERE empid = 1111;
