The document provides information on database management concepts, focusing on Data Manipulation Language (DML) and data abstraction levels. It explains that DML is used for manipulating data in databases and outlines the three levels of data abstraction: physical, logical, and view. Additionally, it discusses various SQL commands related to data manipulation and table deletion, emphasizing their roles in database management.

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2. 1. Which of the following languages is used in application
programs, to retrieve, store, modify, delete, insert and update data
in database?
1. DML
2. DDL
3. DCL
4. TCL
Answer: DML
Concept:
A data manipulation language (DML) is a computer programming
language used for adding (inserting), deleting, and modifying
(updating) data in a database. A DML is often a sublanguage of a
broader database language such as SQL, with the DML
comprising some of the operators in the language.
Hence the correct answer is DML
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3. 2. What is the highest level of data abstraction in the database
management system?
1. Physical level
2. Logical Level
3. View Level
4. Hashing
5. None of these
Answer: View Level
Key Points
Database systems comprise complex data-structures. In order to
make the system efficient in terms of retrieval of data, and reduce
complexity in terms of usability of users, developers use
abstraction i.e. hide irrelevant details from the users. This
approach simplifies database design.
There are mainly 3 levels of data abstraction:
1. Physical: This is the lowest level of data abstraction. It tells us
how the data is actually stored in memory. The access methods
like sequential or random access and file organization methods
like B+ trees, hashing used for the same. Usability, size of
memory, and the number of times the records are factors that we
need to know while designing the database. Suppose we need to
store the details of an employee. Blocks of storage and the amount
of memory used for these purposes are kept hidden from the user.
2. Logical: This level comprises the information that is actually
stored in the database in the form of tables. It also stores the
relationship among the data entities in relatively simple
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4. structures. At this level, the information available to the user at the
view level is unknown. We can store the various attributes of an
employee and relationships, e.g. with the manager can also be
stored.
3. View: This is the highest level of abstraction. Only a part of the
actual database is viewed by the users. This level exists to ease the
accessibility of the database by an individual user. Users view data
in the form of rows and columns. Tables and relations are used to
store data. Multiple views of the same database may exist. Users
can just view the data and interact with the database, storage and
implementation details are hidden from them.
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View 1 View 2 View 3
Logical Level
Physical Level

5. 3. ________is to express database queries and updates.
1. data definition language
2. data manipulation language
3. data control language
4. transaction control language
5. Hypertext Markup Language
Answer: data manipulation language
The correct answer is data manipulation language
• A database system provides a data-definition language (DDL) to
specify the database schema
Example of DDL commands: CREATE, DROP etc.
• A data-manipulation language (DML) is a language that enables
users to access or manipulate data as organized by the appropriate
model
Example of DML commands: INSERT, DELETE etc.
• A data control language (DCL) is used to control access
(Authorization) to data stored in a database
Example of DCL commands: GRANT and REVOKE
• A transaction control language (TCL) is used to control
transactional processing in a database Example of TCL commands:
COMMIT, SAVEPOINT etc
4. Which of the following SQL commands are used to delete a table
from a database?
1. Purge
2. Truncate
3. Delete
4. Drop
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6. Answer: Drop
Key Points
• DROP - It is a Data Definition Language (DDL) Command
which is used to delete, tables, views, triggers, etc from a
database.
• A DROP statement in SQL removes a component from a
relational database management system (RDBMS).
Additional Information
• Data Definition Language (DDL) - Data Definition Language
consists of SQL commands that can be used to define the
database.
• List of DDL commands
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7. 5. Which of the following operation(s) will manipulate data in
MySQL?
1. Delete
2. Update
3. Insert
4. Merge
5. All of the above
Answer: All of the above
Data-manipulation language (DML).
It is a language that enables users to access or manipulate data as
organized by the appropriate model.
Example of DML commands: INSERT, DELETE, UPDATE,
MERGE, SELECT etc.
Explanation:
• Delete will delete the tuples from the relation (table)
• Update will change the value of particular cell in a relation.
• Insert will insert the tuples from the relation. Therefore delete,
update and insert are update operation in SQL
• Merge - UPSERT operation (insert or update)
• Hence all the operation will update in MySQL
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