Chapter 1
Introduction
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Objectives


The basic concepts of database management
The role of data modeling and database design in
the database life cycle
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1.1 Data and Database Management
File system
Data item -> Record -> File
Relational database Attribute -> Tuple -> Table

Database

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It is a collection of interrelated stored data that serves
the needs of multiple users within one or more
organizations, that is, interrelated collections of many
different types of tables.
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1.1 Data and Database Management

DBMS

is a generalized software system for manipulating
databases, and supports:




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Ligical view (schema, subschema)
Physical view (access methods)
DDL
DML
Utilities (transaction management, concurrency control,
data integrity, crash recovery, security)
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1.1 Data and Database Management

Data independence
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
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is the ability to make changes in either the logical or
physical structure of the database without requiring
reprogramming of application programs.
邏輯資料獨立：當Conceptual view改變時，External
view不需改變。
實體資料獨立：當Internal view改變時，Conceptual
view不需改變。
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1.2 Data Modeling and the EntityRelationship Approach


Schema diagram (by Charles Bachman in the
1960s)
ER (by Peter Chen in 1976)
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
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
Simplicity
Readability
The goal of conceptual schema design
The ER model has two levels of definition:
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Simple level (Figure 1.1)
Complex level
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1.3 The Database Life Cycle
The steps of database life cycle (Figure 1.2~1.4)

 Requirement analysis
 by interviewing both producers and users.
 The specification includes the data, the natural data
relationship, and the software platform.
 Logical design: global schema
a.
b.
c.
d.
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ER modeling
View integration
Transformation of the ER model to SQL tables
Normalization of tables
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1.3 The Database Life Cycle
The steps of database life cycle (Figure 1.2~1.4)

 Physical design




The selection of indexes (access methods)
Clustering of data
Data integrity
Denormalization: be refined in limited ways to reflect
query performance
 Data distribution
 Database implementation, monitoring, and
modification
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