3. Student
Std_ID Name
Addr
Sec
DoB
Std_ID Name Addr Sec DoB
189X1A05XY Sree Sanfransisco A 01/01/1999
189X1A05XZ Sri Germany B+ 01/01/2000
ER Model Relational Model
ER Model Vs. Relational Model
4. Naive / Prgmers / Sophisticated / DBA
Appl.
interface
s
Appl.
programs
Query
tools
Admin
tools
Query Processor
Object
code
Compiler
DML
Queries
DDL
Interpreter
Query Evaluation Engine
Storage Manager
Buffer
Manager
File
Manager
Authorization &
integrity manager
Transaction
Manager
Data Indice
s
Data
Dictionar
y
Disk Storage
Users
5. DDL Commands
DDL:
Data Definition
Language
CREATE
ALTER
DROP
RENAME
DML:
Data Manipulation Language
INSERT
UPDATE
DELETE
SELECT
DCL:
Data Control Language
GRANT
REVOKE
COMMIT (TCL)
ROLLBACK (TCL)
6. 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,
7. DDL: Alter
ALTER TABLE table_name ADD 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;
8. DDL Command: DROP &
Rename
Drop table student;
Rename student1 to student2;
TRUNCATE TABLE customer1;
10. DML Example: Insert
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
korth';DELETE FROM Customer1 WHERE Name='Henry Korth' AND
age=60;
11. Today’s Topics
DCL
Entity Relationship Model
Basic concepts
Cardinality of Relationship
ER Diagram Notations
ER Diagrams: Examples
12. 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
14. 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;
15. 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
16. Entity Relationship Model
The ER data model facilitates database design
by allowing specification of an enterprise
schema that represents the overall logical
structure of a database.
The E-R data model employs three basic
concepts: entity sets, relationship sets, and
attributes
17. Entity Sets
Entity: Real-world object distinguishable from other
objects. An entity is described (in DB) using a
set of attributes.
Entity Set: A collection of similar entities. E.g., all
employees.
All entities in an entity set have the same set of attributes.
Each entity set has a key.
Each attribute has a domain.
19. Relationship Sets
Relationship: Association among two or more
entities.
A relationship set is a mathematical relation
among n 2 entities, each taken from entity sets
{(e1, e2, … en) | e1 E1, e2 E2, …, en
En}
where (e1, e2, …, en) is a relationship
22. Attributes
An entity is represented by a set of
attributes, that is descriptive properties
possessed by all members of an entity
set.Example:
customer = (customer_id, customer_name, customer_street,
customer_city )
loan = (loan_number, amount )
23. Attribute types
Simple : Attribute is simple, if its value can not be divided into subparts.
For example Std_ID, GPA.
Composite : Attribute is composite, if its value can be divided into
subparts. Ex: Name: First Name; Middle Name; Last Name
Address: H.No; street; city; pincode
Single-valued : Attribute is a single-valued, if it has only one value for a
particular entity
Multivalued : Attribute is multivalued, if it has a set of values for a
particular entity. Ex: Phone number
Derived: Attribute is a derived, if its value can be derived from the values
of other related attributes or entities. Ex: Age, given dateofbirth
24.
25. ER Diagram Notations
Rectangles represent entity sets
Ellipses represent attributes
Diamonds represent relationship sets
Lines link attributes to entity sets and link entity
sets to relationships sets