
Concept Notes: DBMS, RDBMS & SQL
🔹 1. What is DBMS?
- DBMS (Database Management System) is software used to create, manage, and manipulate databases.
- Examples: MySQL, Oracle, SQLite
🔹 2. RDBMS (Relational DBMS)
- Stores data in tables (rows and columns)
- Uses keys to relate tables:
➤ Primary Key – Uniquely identifies each row
➤ Foreign Key – References a key in another table
✅ Based on relational model introduced by E. F. Codd
🔹 3. SQL – Structured Query Language
SQL is used to interact with relational databases.
Command Type | Examples |
---|---|
DDL (Definition) | CREATE, ALTER, DROP |
DML (Manipulation) | INSERT, UPDATE, DELETE |
DQL (Query) | SELECT |
DCL (Control) | GRANT, REVOKE |
🔹 4. Common SQL Syntax
CREATE TABLE students (
id INT PRIMARY KEY,
name VARCHAR(50),
marks INT
);
SELECT * FROM students WHERE marks > 80;
MCQs – DBMS & SQL (Day 3 Night)
1️⃣ What does RDBMS stand for?
A) Remote Database Management System
B) Relational Database Management System
C) Readable DB Management
D) Row Database Management
2️⃣ Which key uniquely identifies rows in a table?
A) Foreign Key
B) Alternate Key
C) Primary Key
D) Secondary Key
3️⃣ What command is used to retrieve data from a table?
A) GET
B) FETCH
C) SELECT
D) RETRIEVE
4️⃣ Which of these is not a SQL command?
A) DELETE
B) SELECT
C) PRINT
D) UPDATE
5️⃣ Which SQL clause is used to filter records?
A) FROM
B) WHERE
C) HAVING
D) JOIN
6️⃣ What does DML stand for?
A) Data Modeling Language
B) Data Management Language
C) Data Manipulation Language
D) Direct Mapping Logic
7️⃣ Which command creates a table?
A) MAKE TABLE
B) CREATE
C) GENERATE
D) STRUCTURE
8️⃣ Which SQL command is used to remove a table?
A) DELETE TABLE
B) ERASE
C) DROP
D) REMOVE
9️⃣ Which key references the primary key of another table?
A) Unique Key
B) Super Key
C) Foreign Key
D) Composite Key
🔟 What does the *
in SELECT * FROM students;
mean?
A) Select all columns
B) Select first column only
C) Select ID column
D) Select top 1 record
✅ Answer Key
Q.No | Answer |
---|---|
1 | B |
2 | C |
3 | C |
4 | C |
5 | B |
6 | C |
7 | B |
8 | C |
9 | C |
10 | A |
🧠 Explanations
- Q1: RDBMS = Relational Database Management System
- Q2: Primary Key = unique identifier
- Q3:
SELECT
is used to query tables - Q4:
PRINT
is not an SQL command - Q5:
WHERE
filters rows based on conditions - Q6: DML = Data Manipulation Language
- Q7:
CREATE
is used to create structures - Q8:
DROP
removes a table entirely - Q9: Foreign Key = connects to primary key in another table
- Q10:
*
selects all fields from a table
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💬 Comment Task
🗣 Which is confusing – Foreign Key or SQL Commands?
Tell us in comments and we’ll simplify with charts and visuals in tomorrow’s blog or short.