1. Syllabus Study Introduction to database Relational algebra
Relational calculus – tuple relational calculus, domain relational calculus
Normalization – types
Ordbms
Mapping of data into files
Thursday, August 08, 2019

2. Database- Introduction
1. Definition – collection of data – interrelated information’s
Eg – student, customer
2. DBMS- collection of interrelated data and set of programs to access those data.
3. Goal – To provide an environment – convenient and efficient to store and retrieve information from the database
Thursday, August 08, 2019

3. Purpose of Database systems
1.To avoid data redundancy & inconsistency
Eg – address and telephone in a record
2. To avoid difficulty in accessing data
Eg- information extracted manually – avoided
3. It avoids data isolation – avoids files of different formats
4. It supports atomicity – funds transfer must be atomic
5. It supports concurrent accesses
6. Secured
Thursday, August 08, 2019

4. View of Data
Major purpose –db system – to provide users with an abstract view of the data.
The system hides details – how the data are stored and maintained
Several abstractions – physical level , logical level, view level
Physical level – lowest level, how the data are actually stored
Thursday, August 08, 2019

5. Logical level
What data are stored in db, what relationships exist among those data
View level – describes only part of the db.
------diagram---
Thursday, August 08, 2019

6. Entity & Attribute 1. Entity – describes object, action,thing
Eg. Person .. Has set of properties and the values for some set of properties uniquely identify an entity. Eg. Student
Attribute – which further derives the entity.
Eg student regno, student marks, studentcourse, studrollno, custaccno, courseno.
Thursday, August 08, 2019

7. RDBMS Primary data model for commercial data-processing applications.
Relational db – consists of a collection of tables, each – assigned a unique name
A row in a table represents a relationship among a set of values
Correspondence – close relationship between the table and mathematical concept of relation
Thursday, August 08, 2019

8. Basic structure
For each attribute – define a set of permitted values – domain
Eg : consider the account table..3 column headers – branchname, accountno, balance
The relation is
D1*D2*D3, D1- Set of branchnames, D2- set of accountno’s , D3- set of balances.
Tuple – row in a table.
Thursday, August 08, 2019

9. The account relation Branch-name Accountno Balance Sbi A101 500 Cb
700
A365
400
Boi
A785
350
Icici
A111
900
Axis
a555
Thursday, August 08, 2019

10. Database schema Schema – logical design of a db
Concept – relation – programming language – variable
Concept – relation schema – programming language – type definition
In relational db, lowercase – relations, uppercase – relation schema.
Eg – account-schema
Accountschema=(bname, accno,bal)
Thursday, August 08, 2019

11. Schema cont.. Branch-schema = (bname, bcity, assets)
Customer-schema=(custname, custst, custcity)
Depositer-schema = (custname, accno)
Borrower-schema= (custname, loanno)
Loan-schema=(bname, lno, amt)
Thursday, August 08, 2019