BÀI GIẢNG TIẾNG ANH RELATIONAL DATABASES

Learning Objectives Describe the basic of database Explain what a relational database is and how it organizes data Perform simple queries using the Microsoft Access database Describe database systems and the future of accounting

Chapter 5

RELATIONAL DATABASES

ACCOUNTING INFORMATION SYSTEM

Lecturer: Vũ Quốc Thông

Learning Objectives

Describe the basic of database

Explain what a relational database is and how it organizes data

Perform simple queries using the Microsoft Access database

Describe database systems and the future of accounting

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The Basic of Database

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Data Hierarchy

Field (column)

 Attributes about

an entity

Record (row /

tuple)

 Related group

of fields

File (table)

 Related group

of records

Database

 Related group

of files

Picture?

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In short…

5

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File-system v.s Database system

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Limitations of File-based Systems

Separation and isolation of data

Each program maintains its own set of data

Users of one program may be unaware of potentially useful data held by other programs

Duplication of data

Same data is held by different programs

Wasted space and potentially different values and/or different formats for the same item

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Advantages of Database Systems

Data Integration

Files are logically combined and made accessible to various systems

Data Sharing

With data in one place it is more easily accessed by authorized users

Minimizing Data Redundancy and Data Inconsistency

Eliminates the same data being stored in multiple files, thus reducing inconsistency in multiple versions of the same data

Cross-Functional Analysis

Relationships between data from various organizational departments can be more easily combined

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Example of Database system

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Relational Database

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Relational Database

Relational data model represents the conceptual and external level schemas as if data are stored in tables

Table (a File)

Each row (or a tuple) contains data about one instance

of an entity

This is equivalent to a record

Each column contains data about one attribute of an

entity

This is equivalent to a field

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A Relational Table

Column (Field)

Each row contains multiple attributes describing an instance

of the entity In this case, inventory.

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Attributes / Keys

Primary Key

An attribute or combination of attributes that can

be used to uniquely identify a specific row (record)

in a table

Foreign Key

An attribute in one table that is a primary key in

another table Used to link the two tables

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A Relational Table with KEYS

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Examine: Chap05_AcctSalesRDB.accdb

Design Requirements for Relational Database

1 Every column must be single valued

2 Primary keys must contain data (not null)

3 Foreign keys must contain the same data as the primary key in another table

4 All other attributes must identify a characteristic of the table identified by the primary key

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Queries with MS relational database

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DBMS Languages

 Data Definition Language (DDL)

 Builds the data dictionary

 Creates the database

 Describes the subschema

 Specifies record or field security constraints

 Data Manipulation Language (DML)

 Changes the content in the database

 Updates, insertions, and deletions

Structure (Data) Query Language (SQL / DQL)

Enables the retrieval, sorting, and display of data from the database

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Practice with Chap05_AcctSalesRDB.accdb

Microsoft Access Query #1

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Microsoft Access Query #2

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Microsoft Access Query #3

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Microsoft Access Query #5

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Database systems and the future of Accounting

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Database and the future of Accounting

Ad-hoc queries to provide information for decision-making

Financial information is no longer available only in

predefined format

Multiple views of the same underlying phenomenon (e.g

managers will no longer be forced to look at data in the ways predefined by accountants)

Capable of integrating financial and operational data (e.g

customer satisfaction data could be retrieved from DB giving managers more information for decision making)

Relational database increase the use and value of accounting information Accountant must understand database system to use AIS effectively!

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Transform Raw Data into Information

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Transform Raw Data into Information

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Transform Raw Data into Information

Table format

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Transform Raw Data into Information

Graphic format

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More on reading and practice

Reading on textbook

Chapter 4 (p 107 – 109, p 112 - 125)

Doing homework on paper

Discussion questions

Question 4.2, 4.3 and 4.7 (p 128)

Chapter quiz (focus on relevant parts of the lecture)

Quiz of chapter 4 (p 126, 127)

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