SQL, or Structured Query Language, is a powerful and versatile programming language used for managing and manipulating relational databases. With its intuitive syntax and wide-ranging capabilities, SQL has become a cornerstone of modern data management systems, enabling users to interact with databases efficiently and effectively. One of the primary functions of SQL is to retrieve data from databases using queries. These queries allow users to specify the data they want to retrieve, filter it based on certain criteria, and perform various operations on it. SQL queries typically consist of several components, including: 1. **SELECT statement**: The SELECT statement is used to specify the columns of data that should be retrieved from the database. It allows users to choose which fields they want to include in the query's results. 2. **FROM clause**: The FROM clause specifies the table or tables from which the data should be retrieved. It identifies the source of the data for the query. 3. **WHERE clause**: The WHERE clause is used to filter the data based on specific conditions. It allows users to narrow down the results of their query by specifying criteria that must be met by the data. 4. **JOIN clause**: The JOIN clause is used to combine data from multiple tables in a database. It allows users to create relationships between tables based on common fields and retrieve data that spans multiple tables. 5. **GROUP BY clause**: The GROUP BY clause is used to group the results of a query based on one or more columns. It allows users to aggregate data and perform calculations on groups of records rather than individual records. 6. **HAVING clause**: The HAVING clause is used in conjunction with the GROUP BY clause to filter groups of data based on specific conditions. It allows users to apply conditions to groups of records after they have been grouped by the GROUP BY clause. 7. **ORDER BY clause**: The ORDER BY clause is used to sort the results of a query based on one or more columns. It allows users to specify the order in which the data should be displayed. SQL also provides a wide range of functions and operators for performing calculations, manipulating strings and dates, and performing various other tasks. These functions and operators enhance the flexibility and power of SQL queries, enabling users to perform complex operations on their data with ease. In addition to querying data, SQL is also used for managing database structures, creating and modifying tables, defining relationships between tables, and enforcing constraints to maintain data integrity. SQL's data definition language (DDL) allows users to create, alter, and drop database objects such as tables, indexes, and views, while its data manipulation language (DML) allows users to insert, update, delete, and retrieve data from tables. Overall, SQL is a fundamental tool for working with relational databases, providing users with the ability to retrieve, manipulate, and manage

1. DATABASE MANAGEMENT
SYSTEMS
1

2. Topics Covered
1. DDL
2. DML
3. DCL
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3. 1. DDL Commands
DDL:
Data Definition
Language
 CREATE
 ALTER
 DROP
 RENAME
 DELETE
 SELECT
DCL:
DML:
Data Manipulation Language
 INSERT
 UPDATE
Data Control Language
 GRANT
 REVOKE
 COMMIT (TCL)
 ROLLBACK (TCL) 3

4. 1.1 DDL: Create
CREATE TABLE
CUSTOMER1(
ID Number(2),
NAME NVARCHAR2 (20),
AGE INT,
ADDRESS NVARCHAR2
(30) ,
SALARY DECIMAL (10, 2)
create table cust_temp as
select id, name from
customer1;
CREATE TABLE STUDENT2
(
ID INT NOT NULL,
NAME VARCHAR(20) NOT
NULL,
AGE INT NOT NULL, 4

5. 1.2 DDL: Alter
 ALTER TABLE table_nameADD column_name
datatype;
 ALTER TABLE table_name DROP COLUMN
column_name;
 ALTER TABLE table_name MODIFY COLUMN
column_name datatype;
 ALTER TABLE table_name MODIFY column_name
datatype NOT NULL; 5

6. 1.3 DDL Command: DROP &
Rename
 Drop table student;
 Rename student1 to student2;
 TRUNCATE TABLE customer1;
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7. 2. DML: Data Manipulation Language
 INSERT
 UPDATE
 DELETE
 SELECT
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8. 2.1 DML Example: Insert, Select,
Update
insert into customer1values(90, 'Codd',60,'San Fransisco',
150000);
insert into customer1 values(&id,
'&name',&age,'&address',&salary);
SELECT * FROM EMPLOYEE
UPDATE Customer1 set ID=18, WHERE Name='henry D
k
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o
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r
t
E
h
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'
;
E
FROM
Customer1 WHERE Name='Henry Korth' AND age=60;
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9. 3. DCL: Data Control Language
 GRANT : used to grant or give the privileges.
 REVOKE : used to avoid or object the privileges.
 COMMIT: used to save the data permanently.
 ROLL BACK : Used to revert changes in the
transactions since the last commit or rollback
command was issued
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10. 3.1 DCL: Commit
DELETE FROM
CUSTOMERS
WHEREAGE = 25;
SQL> COMMIT;
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11. 3.2 Rollback
 ROLLBACK command is the transactional
command used to undo transactions that have
not already been saved to the database.
 This command can only be used to undo
transactions since the last COMMIT or
ROLLBACK command was issued.
 DELETE FROM CUSTOMERS WHERE AGE =
25; 11

12. 3.3 DCL : Grant & Revoke
create user korth identified by henry
🞑 Connect as system/ora10g
GRANT SELECT, INSERT, UPDATE, DELETE
ON Emp_Det TO korth;
REVOKE DELETE ON Emp_details FROM
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