Using Data Flow Diagrams

Dengan menggunakan kombinasi dari 4 simbol DFD, analis sistem dapat membuat gambaran proses suatu sistem.

Keuntungan Pendekatan DFD:

Selain menjelaskan proses aliran data dalam suatu sistem, ada 4 keuntungan lainnya:

1. Kebebasan mengimplementasikan secara teknis kedalam sistem lebih dahulu.
2. Lebih mengerti hubungan anatar sistem dan subsistem.
3. Mengkomunikasikan model sistem sekarang kepada pengguna atau kepada anggota team projek melalui diagram alur data (DFD).
4. Menganalisis sistem yang diusulkan, jika data dan proses yang telah didefinisikan,

Gambar 1: Simbol yang digunakan dalam DFD

The double square is used to depict an external entity that can send data to or receive data from the system. The external entity, or just entity, is also called a source or destination of data.

Partitioning Data Flow Diagrams 

Partitioning is the process of examining a data flow diagram and determining how it should be divided into collections of manual procedures and collections of computer programs.

There are six reasons for partitioning data flow diagrams:

1. Different user groups. Are the processes performed by several different user groups. An example is the need to process customer returns and customer payments in a department store. Each group needs a different screen for recording the particulars of the transaction, either a credit screen or a payment screen.
2. Timing. Examine the timing of the processes masing2 data flow

3. Similar tasks. If two processes perform similar tasks, they may be grouped into one computer program.

4. Efficiency. Several processes may be combined into one program for efficient processing. For example, if a series of reports needs to use the same large input files, producing them together may save considerable computer run time.

5. Consistency of data. Processes may be combined into one program for consistency of data. For example, a credit card company may take a “snapshot” and produce a variety of reports at the same time just so figures are consistent.

6. Security. Processes may be partitioned into different programs for security reasons. A dashed line may be placed around Web pages that are on a secure server to separate them from those Web pages on a server that is not secured. AWeb page that is used for obtaining the user’s identification and password is usually partitioned from order entry or other business pages.

Gambar 2: contoh partisi DFD

Penulis: Yusia /Kaleb
Referensi:
[1] Kendall, K.E., Kendall, J.E., Systems Analysis and Design. Prentice Hall. 2011. New Jersey, USA.