Database
Management
Systems
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Instructor: Yrd. Doç. Dr. Cengiz Örencik
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E-mail: cengizorencik@beykent.edu.tr
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Course material
http://myweb.sabanciuniv.edu/cengizo/cour
ses
◦ all the notes will be shared there
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Not required
You may use any database book
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Database Management Systems – 3rd Edition
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◦ Ramakrishnan and Gehrke
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Midterm
Inclass quizzes (2)
Final
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Hws
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40%
10%
50%
◦ Self study
◦ Not to be graded
4
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Managing data
Introduction to Database design
◦ Entities, attributes, relationships, etc.
◦ ER model
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Relational Model
◦ Representing data
◦ Create, modify, query…
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Relational Algebra vs. SQL
Storage and Indexing
Transaction Management
◦ Concurrency control
◦ Crash recovery
5
Database Management System (DBMS)
provides….
… efficient, reliable, convenient, and safe
multi-user storage of and access to massive
amounts of persistent data.
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Massive – terrabytes/day
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Persistent
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Safe – hard/software failure, power cut
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Multi-user
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Convenient
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Efficient
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Reliable
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A Database Management System (DBMS) is a
software package designed to store and manage
databases
We will not consider:
Database applications may be programmed via
“frameworks”
◦ Environments that help to develop program
◦ Ruby on rails, Django…
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DBMS may run in conjunction with “middleware”
◦ Web servers that interact with database
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Data-intensive applications may not use DBMS at
all
◦ Store everything on files
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Data independence
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Efficient access
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Data integrity and security
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Uniform data administration
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Reduced application development time
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◦ Application programs don’t need details of data representation
and storage
◦ A variety of techniques
◦ Enforce constraints, access control…
◦ How different groups of users use it
◦ Organized to minimize redundancy
◦ DBMS support most common important functions
Concurrent access, recovery from crashes
◦ Multiple users use it without conflict
◦ Protect from effects of system failures
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Data described as a set of records
Example: Student information in a university
Students(sid: integer, name: string, mail:
string, age: integer, gpa: real)
Sid
Name
Mail
Age
Gpa
53666
Jone
jone@cs
20
3.2
53680
Smith
smith@cs
21
2.9
53442
Smith
smith@math
19
3.85
53123
Alice
alice@ee
21
3.5
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Relation  student
Each column  attributes
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Each row is a record that describes a student
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Integrity constraints
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◦ Sid must be unique
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What is the name of the student with sid
53680?
How many students are enrolled to DBMS
course?
What fraction of students of DBMS course get
a grade better than BB?
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DBMS implementer
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Database designer
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Database application developer
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Database administrator
◦ Builds the system
◦ Works for IBM or Oracle
◦ Interact users
◦ Establishes the schema - relations
◦ How to structure – how to store
◦ Builds the programs that operate on the database
◦ Use tools DBMS provides
◦ Usually not computer professionals
◦ loads the data, keep it running
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DBMS used to maintain, query large datasets
Benefits include recovery from system
crashes, concurrent access, quick application
development, data integrity and security
DBAs hold responsible jobs
and are well paid
Whether you know it or not, you’re using a
database every hour