Chapter 3

CHAPTER III

REVIEW REFERENCES

3.1       DEFINITION OF DATABASE SYSTEM

There are several definitions of database systems, namely:

·         The database is a collection of files that have links between one file with another file so as to form a building data to inform a company or agency in certain restrictions [http://www.gudangmateri.com/2010/04/definisi-base-data].

·         Database System is a system consisting of components components (hardware, software, brainware, databases) are mutually has a dependence and has the common goal of integration of all these components. [Fathansyah, 2004]

·         computerized system whose main purpose is to maintain information and make such information available when is required. [Abdul Kadir, 2001]

So the database system is a set of data collection mutual dependence and has the same purpose.

3.2       Relational Database

Relational Database in a simple sense can be said as a database in which tables are mutually relate to one another [Fathansyah, 2002]. Relationships or connectedness between one table to another table is determined based on the rule-certain rules. Relationships between tables are often referred to as relationship. The types of relationships between tables or relationships have 3 kinds, namely:

·         The relation 1 to 1 (one to one relation) or one to one.

·         The relation 1 to n or n to 1 (relation 1 to many or many to one) or
one to many.

·         The relation n to m (relation many to many) or many to many.

3.3       DATABASE DESIGN PHASE PROCESS

Database design process include:

Phase 1: Collect data and analyze

a.       Determine the user groups and areas of application.

b.      Review the existing documentation.

c.       Environmental analysis and data processing operations.

d.      The questionnaire and interview.

Phase 2: Designing Database conceptually

The purpose of this phase is to produce a conceptual schema for the data base
which depends on a specific DBMS, using a high level data models like ER models. In the conceptual scheme detailing database applications that are known and transactions
possible.

Phase 3: Selecting a DBMS

Selection of DBMS determined several factors, including technical factors,
economic, and political organizations. Examples of technical factors: the existence of a DBMS in performing their duties, such as the types of DBMS (relational, Network, Hierarchical, etc.), storage structures and pathways DBMS that supports access, users, and others.

Phase 4: Designing a Logical Database

Designing Database secra logic is the process for transform the conceptual data model into logical data model. The goal is to translate the conceptual design (which reflect the needs of the organization's data that we analyze in stage earlier) to the design of logic that can be directly implemented on the database system chosen. Process that occurs namely:

a.       Transform the E-R diagram to relations.

b.      Normalization

Phase 5: Designing the Physical Database

This phase is the process of choosing the storage structures and access routes to the database files to achieve the best Performance various kinds of applications. During this phase, the designed specification-specifications for the base data stored associated with physical storage structure, placement record, and the access point related to the internal schema.

3.4       Data Flow Diagrams (DFD)

Data Flow Diagrams (DFD) is a modeling tool that system allows professionals to describe the system as a network of functional processes are connected to each other by flow data, either manually or computerized [Leman, 1998].

Before implementing the program, then do manufacture DFD or Data Flow Diagram. Notation used in DFD can seen as follows:

1.      Process is a symbol that converts data from a form into other forms.

                                                  

Figure 3.1 Symbols Process

2.      Data flow or data flow is a flow showing transfer data from one section to another within a system.

Figure 3.2 Data Flow Symbols

3.      Data Store is where to store data in a system, either manually or electronically.

  Figure 3.3 Symbol Data Store

4.      Data Source is the source of the data shows an organization or
individuals who enter data into the system.

Figure 3.4 Symbol Data Source

3.5       ENTITY Relational Diagrams (ERD)

Definition of ERD In software engineering, an Entity-Relationship Model (ERM) is an abstract and conceptual data representation. Entity-Relationship is one of the methods modeling database used to generate the schema for this kind of conceptual / semantic data model of the system [Fathansyah, 2002]. Where the system often has a relational database, and top-down provisions. Diagram for Entitiy-Relationship model illustrates is called Entitiy-Relationship diagrams, ER diagrams, or ERD.

There are a number of conventions regarding the ERD notation. Notation
often used for classical conceptual model. Various notations Another also used to describe the logical and physical from a data base, one of which is IDEF1X.

Figure 3.5 Notation symbolic ERD

3.6       Microsoft Access 2007

In Microsoft Access 2007, there are components which can be used to create database applications. The components include:

1.      Tables : Form of tables of data collection which is a componenta primary database.

2.   Query : Query is the actual data processing tools in the Access database. Query has many functions, but the most frequently used is the bolt to display data
specifics of a database.

3.     Form : The bias window is changed to remedy program interface.

4. Report : Used to display report data analysis results. Report represents certain information from the database.

5.      Macros : Perntah-commands to automate frequentused in processing the data.

6.  Toolbox : To add elements into the program interface form used tools or controls contained in the toolbox.