Kế toán, kiểm toán - Chapter 5: Learning objectives

Vũ Quốc Thông 2/27/2015 1 Chapter 5 RELATIONAL DATABASES HO CHI MINH CITY OPEN UNIVERSITY ACCOUNTING – AUDITING FACULTY 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 5-2 Vũ Quốc Thông 2/27/2015 2 The Basic of Database 5-3 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? 5-4 Vũ Quốc Thông 2/27/2015 3 In short 5 ? ? ? File-system v.s Database system 5-6 Vũ Quốc Thông 2/27/2015 4 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. 5-7 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. 5-8 Vũ Quốc Thông 2/27/2015 5 Example of Database system 4-9 Relational Database 5-10 Vũ Quốc Thông 2/27/2015 6 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 5-11 A Relational Table R o w ( R e c o rd ) Column (Field) Each row contains multiple attributes describing an instance of the entity. In this case, inventory. 5-12 Vũ Quốc Thông 2/27/2015 7 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 5-13 A Relational Table with KEYS 5-14 Examine: Chap05_AcctSalesRDB.accdb Vũ Quốc Thông 2/27/2015 8 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. 5-15 Queries with MS relational database 5-16 Vũ Quốc Thông 2/27/2015 9 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 5-17 Practice with Chap05_AcctSalesRDB.accdb Microsoft Access Query #1 5-18 Vũ Quốc Thông 2/27/2015 10 Microsoft Access Query #2 5-19 Microsoft Access Query #3 5-20 Vũ Quốc Thông 2/27/2015 11 Microsoft Access Query #4 5-21 Microsoft Access Query #5 5-22 Vũ Quốc Thông 2/27/2015 12 Database systems and the future of Accounting 5-23 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! 5-24 Vũ Quốc Thông 2/27/2015 13 Transform Raw Data into Information 5-25 Transform Raw Data into Information 5-26 Vũ Quốc Thông 2/27/2015 14 Transform Raw Data into Information Table format 5-27 Transform Raw Data into Information Graphic format 5-28 Vũ Quốc Thông 2/27/2015 15 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) 5-29