1. Databases and Data Modeling for Accounting Information Systems

2. Databases and Data Modeling for Accounting Information Systems
An Overview of Databases
A database is a large collection of related data that are stored in computerized and linked files
Not every collection of data is database

3. Databases and Data Modeling for Accounting Information Systems
The importance of database to AISs
Valuable information
Volume
Complexity
Privacy
Irreplaceable data
Internet users

4. Databases and Data Modeling for Accounting Information Systems
Storing Data in Databases
To be useful, the data in an organization’s databases must be stored and organized efficiently.
Three important concepts are :
Data hierarchy
Bit → character→ data field→
record→ file →database
Record structures
Record keys
primary key
Secondary key
foreign key

5. Databases and Data Modeling for Accounting Information Systems
How to Create Databases With REA
The REA is a tool for designing databases.
Using this model, an AIS captures data about an organization’s resources, events and agents (REA).
Resources are an organization’s assets.
Events are identifiable activities associated with a business processes.
Agents are the people associated with business activities.

6. Databases and Data Modeling for Accounting Information Systems
How to Create Databases With REA
REA models requires some steps :
Identify business and economic events .
Identify entities
Identify relationships among entities
Create entity relationship diagrams
Identify the attributes of data entities
Create database tables and validate the database

7. Databases and Data Modeling for Accounting Information Systems
How to Create Databases With REA
Economic events : impact an organization's financial statements and are captured in accounting transactions .
Business events : do not affect financial statement but can impact an organization in a value – added way .
Database entities : include business and economic events + information about who and what was involved in those activities .

8. Databases and Data Modeling for Accounting Information Systems
Entity-Relationship
The cardinality of a relationship describes the number of occurrences of one entity that may be associated with a single occurrence of the other entity.
One-to-one (1:1)
One-to-many or many-to-one (1:N), (N:1)
None to one or none to many ( 0:1) , (0:N)
Many-to-many (N:N)
Cardinalities provide useful information about the nature of the company being modeled and the business policies that it follows.

9. Databases and Data Modeling for Accounting Information Systems
Entity-Relationship Diagrams
An entity-relationship (ER) diagram graphically depicts a database’s contents.
← ovals denote attribute
← connecting lines show
relationship
←a rectangle depicts of
entity
the diamond
←describe the
Social
Security
number
Hourly
pay
Rate
Date Of
hire
Sales person
Is made by
Sale
Sales person

10. Databases and Data Modeling for Accounting Information Systems
Attributes of entities
Two guidelines we can use to decide what to include as attributes of an entities :
The attributes should describe one entity and that entity only .
To keep in mind that the attributes included in the tables will drive the outputs of the database system.

11. Databases and Data Modeling for Accounting Information Systems
Create Database Records
A particular method used to organize records in a database is called the database’s structure.
The objective is to develop this structure efficiently so that data can be accessed quickly and easily.
Three types of structures are:
1) hierarchical 2) network 3) relational.

12. Databases and Data Modeling for Accounting Information Systems
Hierarchical Structures
Accounting data are often organized in a hierarchy.
A hierarchical structure has successive levels of data in an inverted treelike pattern, also known as tree structures.
Higher level records are parent records and lower level records are child records.
Two records on same level are sibling records.

13. Databases and Data Modeling for Accounting Information Systems
Network Structures
Databases can use a network
structure to link related records
together and capture many-to-many relationships.
The linking is accomplished with pointer fields.
The pointers maintain the data relationships.

14. Databases and Data Modeling for Accounting Information Systems
Relational Structures
Relational databases are more flexible.
Users can define relationships at the time the database is created or at later points in time.

15. Databases and Data Modeling for Accounting Information Systems
Normalization
Flat files are files with no sequence or order to them, except perhaps chronological.
Flat files make it almost impossible to find a particular record easily or use file data productively.
Normalization is a process of examining and arranging file data in a way that enables designers to avoid problems when these files are used or modified later.

16. Un-normalized Parking Ticket Data (0 Normal Form)
Databases and Data Modeling for Accounting Information Systems
Un-normalized Parking Ticket Data
(0 Normal Form)
Social Security Number
Last Name
First Name
Phone No.
License
State
Number
Ticket No
Date
Code
Fine
Curry
Dorothy
(916) CA
123MCD
10151
10/15/98 A
$10
10152
10/16/98 B
$20
10121
11/12/98
Fong
May
(916)
253DAL
10231
10/23/98 C
$50
12051
12/05/98

17. Databases and Data Modeling for Accounting Information Systems
First Normal Form
A database is in first normal form (1NF) if all the record’s attributes (data fields) are well defined and the information can thus be stored in a flat file.
Problems:
data redundancy
insertion anomaly
deletion anomaly

18. First Normal Form Social Security Number Last Name First Name
Databases and Data Modeling for Accounting Information Systems
First Normal Form
Social Security Number
Last Name
First Name
Phone No.
License
State
Number
Ticket No
Date
Code
Fine
Curry
Dorothy
(916) CA
123MCD
10151
10/15/98 A
$10
10152
10/16/98 B
$20
10121
11/12/98
Fong
May
(916)
253DAL
10231
10/23/98 C
$50
12051
12/05/98

19. Databases and Data Modeling for Accounting Information Systems
Second Normal Form
* A database is in second normal form (2NF) if it is in first normal form and all the data items in each record depend on the record’s primary record key.
* This approach results in a more efficient design and eliminates much of the first file’s data redundancy.

20. Second Normal Form Car Registration File Social Security Number
Databases and Data Modeling for Accounting Information Systems
Second Normal Form
Car Registration File
Social Security Number
Last Name
First Name
Phone No.
License Plate
State Number
Curry
Dorothy
(916) CA
123MCD
Fong
May
(916)
253DAL .
Ticket File
Ticket No
Date
Code
Fine
[License Plate] State Number
10151
10/15/98 A
$10 CA
123MCD
10152
10/16/98 B
$20
10121
11/12/98
10231
10/23/98 C
$50
253DAL
12051
12/05/98

21. Databases and Data Modeling for Accounting Information Systems
Third Normal Form
Our goal is to create a database that is minimally in third normal form (3NF).
A database is in third normal form if it is in second normal form and contains no transitive dependencies - i.e., no relationships in which data field A determines data field B.

22. Third Normal Form . Car Registration File Ticket File
Databases and Data Modeling for Accounting Information Systems
Third Normal Form
Car Registration File
Social Security Number
Last Name
First Name
Phone No.
License Plate
State Number
Curry
Dorothy
(916) CA
123MCD
Fong
May
(916)
253DAL .
Ticket File
Violation Code File
Ticket No
Date
[Code]
[License Plate]
State Number
10151
10/15/98 A CA
123MCD
10152
10/16/98 B
10121
11/12/98
10231
10/23/98 C
253DAL
12051
12/05/98
Code
Fine
Explanation A
$10
Meter expired B
$20
Parking in no-parking zone C
$50
No parking sticker

23. Database Management Systems
Databases and Data Modeling for Accounting Information Systems
Database Management Systems
A database management systems (DBMS) is a set of separate computer programs that enable users to create, modify, and utilize database information more efficiently.
The data definition language (DDL) of a DBMS enables users to define the record structure of any particular database table.
The data manipulation language (DML) enables users to perform tasks such as querying, changing records and deleting records.
Many relational databases support structured query language (SQL).

24. Databases and Data Modeling for Accounting Information Systems
Data Normalization for Relational DBMS
EMP#
DEPT#
EMP NAME
JOB CODE
JOB TITLE
LOCATION
HOURS WORKED
120 01
Abriel 1
Accountant
New Orleans 37 08
Abrial
Los Angeles 12
121
Bayer 45 21
New York
107
270
Boudreaux 2
Supervisor 10
Baudreaux 78
273
Wolbrette 3
Manager 22
274
Scanlon 41
279
Richards 27 20 51
301
Daly 16

25. data manipulation language (DML)
Databases and Data Modeling for Accounting Information Systems
data manipulation language (DML)
The totality of information in a database and the relationships of its tables (records) is called the database schema.
The database schema is a map or plan of the entire database.
Any particular user or application program will be interested in only a subset of the schema, called the subschema.
A database must be flexible enough to satisfy the subschema uses required.

26. Example: Schemas and Subschemas
Databases and Data Modeling for Accounting Information Systems
Example: Schemas and Subschemas
Schema for a Customer Record
ACCOUNT-NUMBER
CUSTOMER-NAME
CUSTOMER ADDRESS
SALES-DIVISION
CREDIT-LIMIT
BALANCE
CREDIT-TERMS
TOT-YEARS-SALE
DATE-RECENT-SALE
Subschema for a Sales Order Entry Application
ACCOUNT-NUMBER
CUSTOMER-NAME
CUSTOMER-ADDRESS
CREDIT-LIMIT
BALANCE
CREDIT-TERMS
Subschema for a Sales Analysis Application
SALES-DIVISION
TOT-YEARS-SALES

27. Operate Relational Database Using Query Language (DML)
Databases and Data Modeling for Accounting Information Systems
Operate Relational Database
Using Query Language (DML)
The SELECT Operation
Query language commend: SELECT ABBOTT OF EMPLOYEE DISPLAY EMP NAME AND JOB
The PROJECT Operation
Query language commend: PROJECT EMP NO AND PAY RATE OF PAY-RATE
EMP#
EMP NAME
JOB 11
Smith, A. 4 14
Garcia, B. 2 27
Wong, C. 3 29
Riley,D. 33
O’Hara, E. 1 36
Weiss, F. 41
Abbott, G. 45
Powski, H.
PROJECT
EMP#
HIRE
DATA
PAY
RATE 11
19X9
10.00 14
19X8 27 29 33
20.00 36 41 45
EMP#
PAY
RATE 11
10.00 14 27 29 33
20.00 36 41 45
SELECT
Display: EMP NAME JOB
Abbott,G

28. Operate Relational Database Using Query Language (DML)
Databases and Data Modeling for Accounting Information Systems
Operate Relational Database
Using Query Language (DML)
The JOIN Operation
Query language commend: JOIN EMPLOYEE WITH JOB/DEPT DISPLAY DEPT AND NAME
JOIN
EMP#
EMP NAME
JOB 11
Smith, A. 4 14
Garcia, B. 2 27
Wong, C. 3 29
Riley,D. 33
O’Hara, E. 1 36
Weiss, F. 41
Abbott, G. 45
Powski, H.
JOB
DEPT 1 2 3 4
EMP#
EMP NAME
JOB
DEPT 11
Smith, A. 4 2 14
Garcia, B. 27
Wong, C. 3 1 29
Riley,D. 33
O’Hara, E. 36
Weiss, F. 41
Abbott, G. 45
Powski, H.

29. Online Analytical Processing
Databases and Data Modeling for Accounting Information Systems
Online Analytical Processing
Complex multidimensional data analysis performed on database information is called online analytical processing (OLAP).
OLAP packages allow end users to perform their own database analysis, including data mining.

30. Object-Oriented and Multimedia Databases
Databases and Data Modeling for Accounting Information Systems
Object-Oriented and Multimedia Databases
* The object-oriented database (OODB) is a type of database that contains both the text data of traditional databases, plus information about the set of actions that can be taken on the data fields.
* Most OODBs are multimedia databases that can include graphics, audio information and animation.

31. Characteristics of a Data Warehouse
Databases and Data Modeling for Accounting Information Systems
Characteristics of a Data Warehouse
A data warehouse pools data from separate applications into a large common body of information.
Characteristics of data warehouses
Data are “clean” of errors and defined uniformly.
Data are stored in several databases, not just one.
Data Warehouses span a longer time horizon than the company’s transaction systems.
The data relations are optimized for answering complex questions.

32. Advantages of Data Warehouse
Databases and Data Modeling for Accounting Information Systems
Advantages of Data Warehouse
* Data are “clean” of errors and defined uniformly.
* Data are stored in several databases, not just one.
* Data Warehouses span a longer time horizon than the company’s transaction systems.
* The data relations are optimized for answering complex questions.
* Make organizational information available on a corporate-wide basis.
* Facilitates data mining and enables users to identify
target markets or its most desirable customers.

33. Databases and Data Modeling for Accounting Information Systems
PREPEARED BY :
EMAN AL AQEEL