INTRODUCTION OF
DATABASE
By
Hendra Achmadi MM, MAcc.
Database Environment
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Database Management System (DBMS): a DBMS is a
collection of programs that enables users to create and maintain
a database. The DBMS is a general-purpose software system
used for defining, constructing, and manipulatingdatabases.
Defininga database involves: specifying data types, structures,
and constraints for the data to be stored in the database.
Constructinga database is the process of storing the data
itself.
Manipulatinga database includes functions such as querying
the database to retrieve specific data, updating the database to
reflect changes, and generating reports from the data.
Database System Environment
Database System Environment
Data
Hardware
Software
Procedure People
Three Level ANSI-SPARC ( The American National
Standards Institut, Standards Planning and Requirement
Committee Architecture)
User 1
View 1
•All Entities, attribute, relationship
•Constrain in data
•Security and integrity information
•Storage space allocation for data
and indexes
•Storage size of data
User 2
View 2
Conceptual
Schema
Internal
Schema
•Data placement
•Data compression and encryption
Database
User 3
View 3
Characteristics of the database processing approach
In traditional file processing, each user defines and implements
the files needed for a specific application. When users are
interested in the same data, each user maintains separate files
and programs to manipulate these files. This redundancy results
in wasted storage space and in redundant efforts to maintain
common data up-to-date.
In the database approach, a single repository of data is
maintained and accessed by many users. This approach has the
following characteristics:
• Insulation between programs and data
• Support of multiple views of the data
• Sharing data and multi-user transaction processing
J. Valenzuela, INSY 3400, Fall 2001
People related to the database
environment
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Data & Database administrators: A DBA oversees
and manages the database environment. The DBA is
responsible for authorizing access to the database,
monitoring its use, and acquiring software and
hardware resources as needed.
Database Designers: A DBD is responsible for
identifying the data to be stored, for choosing
appropriate structures to store this data.
End users: These are the people who jobs require
access to the database.
The Relational Database
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Database Relational:
Dipandang oleh user/pengguna sebagai
himpunan relation ( Table)
Struktur Table :
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Terdiri dari bagian Heading dan Body
Bagian Heading sebagai himpunan attribute
Bagian Body sebagai himpunan tuple, dengan
setiap tuplenya adalah himpunan pasangan
attribute dan nilainya
Setiap tuple didefinisikan unik oleh primary key
The Relational Database
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Example 1 – single user
A painter paints houses of customers.
The customers are referred by other
persons (sources).
The Relational Database
Gives the relations (tables) in the database
The Relational Database
Example 2 -multiple users (manager – salesclerks)
A music shop (Treble Clef Music) rents music
instruments and keeps track of all invoices
Example-4
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Reservation center of a hotel
• promotion of the hotel
• register website visitors for later promotion
• store and manage reservations Multimedia data (photos, video clips,
sound)
• Clients, who use a browser
• DBMS managers, use the DBMS
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Data separated and isolated;independent files
Data often duplicated;
Application programs dependent on file format;
Files are often not compatible with one another;
File Processing System
File Processing System
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different formats for
compatible data
It is difficult to
represent data in
users’ perspectives;
difficult to represent
relationships
File Processing System
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Integrated data; only 1 database
Reduced data duplication;
Program/Data independence;
change format, relations, no consequences on programs
Easier representation of the user perspectives;
relationships are part of the database
a database is a self-describing collection of integrated records.
self-describing : data dictionary, metadata, structure of DB
integrated : files, metadata, indexes, application metadata.
Querying, updates ↔transactions
Short History of DBMS
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50’s file systems
60’s network, hierarchical DB
1970 Codd: Relational DB
70’s implementation of RDBMS
80’s introduction of microcomputer DBMS: dBase
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80-90’s LAN, client-server database architecture
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90’s DBMS and Internet, distributed databases
Currently:
data mining
special purpose DB’s : spatial, very large, multimedia • object-oriented DB
XML
Komponen Utama RDBMS
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System Service:
Komponen yang merupakan fungsi
pendukung operasi sistem, komunikasi
operator, logging
Locking Service:
Komponen yang merupakan fungsi kendali
dalam mengelola akses data bersama
Database Service:
Komponen yang fungsi pendukung definisi,
pembacaan dan pemutahiran data.
Introduction to Database Design workshop: Data
collection: Questions used in this exercise
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(Definition/description) Describe to me unambiguously the data that the field contains.
(Length) What’s the longest # characters or the largest amount it could contain? (Realistically speaking)
(Character support) Is every character on the keyboard valid to enter in this field, or only some characters?
(Required value) Must the field have some value in it? Should we require the user to enter a value for that field?
(Null support) Could that field be empty or unknown and still be valid?
(Uniqueness) Must the value entered into the field be unique among all the records? Could more than one record
have the same value entered into that field?
(Values entered by system vs. user) Is there a way that we could fill in the value of this field for the user, without
asking them to type it in? Where would the value of that field come from?
(Default value) Is there a value that’s the most common value for the field, the most likely value for the field, the
most likely thing the user would type in? This may be governed by business rules, not by the data itself.
(Type of key) Is the field a key? If so, what type of key is it?
(Edit rule) When the record is first created, does a value have to be entered, or can it wait until later? Can the user
change the value after the record is created?
(Comparisons allowed) Does it make sense to compare this field to other fields or other values that we know? Does it
make sense to compare the value of this field on this record to that on another record? What comparison might we
make?
(Operations allowed) Does it make sense to perform mathematical operations on this field? Would those operations
involve the same field on other records, or other fields in our database?
(Range of values, picklist) Are there any fields for which we could realistically enumerate every possible value this
field could contain? What are they?
(Input mask) Consider our Friend’s birthday field. What problems could we have with this field when multiple people
start typing data into this field? How can we generically describe a standard for entering data into this field? Are
there other fields with this problem?
(Range of values, Decimal places) Find a numeric field. What’s the largest value it could contain? (Realistically
speaking) Smallest? How many decimals does it make sense to store in this number? (We don’t have a good example
of this in the address database.)