Computer Augmented Accounting
Systems Development Life Cycle (SDLC)
Logical Design for Database Systems (Chapter 8)
June 11th, 2013
To design a system, you have to go through logical data and process modeling, model integration, translating logical data and process models to physical models, documentation of models, and lastly, a feasibility analysis.
The logical data model is a comprehensive structured model that is a representation of the data items of relevance to system users. A popular tool for conceptual data modeling is the Entity-Relationship (ER) diagram. ER modeling uses rectangles to represent entities and diamonds to represent relationships. The extended entity relationship (EER) diagram shows attributes for each entity and relationship, the primary key in each entity, the relationship (if applicable), and the cardinality of relationships.
Data modeling is oriented towards the data items of interest while process modeling focuses on the procedures that modify data items. A commonly used tool for process modeling is the data flow diagram (DFD). Model integration involves mapping the ER entities and the DFD processes to one another. Each "event entity" in the ER diagram will have a corresponding "process" in the DFD.
Unified Modeling Language (UM) is used for specifying, constructing, visualizing, and documenting the artifacts of a software-intensive system. The UML equivalents of "entity", "instance of entity", "relationship", and "attributes" are "class" (terms under the entity relationship model), "object", "association", and "attributes", respectively.
The physical model contains specifics of relevance to a particular database management system (DBMS). The first step in the physical design process is the translationof the logical model to a physical model. EER and DFD diagrams are mapped to tables and forms in a DBMS. Input forms and report formats are designed in this stage of the SDLC. Documentation is aimed at creating detailed written specifications that will facilitate the systems development process.
The SDLC is a project that should be managed carefully. After the project tasks have been identified and time estimates developed, a number of project management techniques can be used to control and monitor the SDLC process. Two popular techniques are the Pert and Gantt chart.
The SDLC is a very long process and users' needs might have changed a lot during the course of the process. To respond to this, tools to speed up application development include computer assisted engineering (CASE), which involves automating activities at various stages in the SDLC. Another way is to increase involvement. Rapid application development (RAD) is a process where steps that look like they are sequential are performed at the same time. It involves switching back and forth between analysis, design, and development. Another method is joint application development (JAD). It makes users and analysts work closely together during analysis and design. The user commitment to the system is enhanced.
Systems Development Life Cycle (chart): 10:51
Systems Design: 13:47
Logical Design - Logical Data Model: 14:18
Simple ER Diagram: 15:33
Simple DFD: 19:58
Object-oriented modeling: 25:35
Physical Design: 26:59
Systems Development: 30:51
Systems Development (Part 2): 32:29
System Implementation: 40:08
Systems Operation & Maintenance: 53:13
Project Management Techniques: 55:20
PERT Chart of Systems Analysis Steps: 56:18
Gantt Chart: 1:02:16
Alternatives to the Traditional SDLC: 1:03:59
Tools to Speed up Application Development: 1:04:28
Increasing User Involvement: 1:06:20
Software Package Acquisition: 1:09:38
Selecting an Accounting Software Package: 1:11:09
Logical Data Modeling: 1:35:10
ER Diagrams: 1:35:36
ER Figures: 1:36:32
ER (Entity Relationship): 1:38:31
Extended Entity-Relationship (EER) Model: 1:41:01
EER Figure: 1:55:40
EER Conventions and Interpretation: 1:59:35
Data Flow Diagrams (DFDs): 2:05:44
DFD Symbols: 2:06:35
DFDs (further explored): 2:06:55
Job Recording & Assignment
Information System Context Diagram: 2:07:35
DFD Level 0: 2:10:32
DFD Level 1: 2:17:23
General Guidelines for Constructing a DFD: 2:27:27
Event-Oriented Modeling for
Designing Business Information Systems: 2:27:31
Event-Oriented Modeling Using the REA Framework: 2:34:26
REA Pattern (chart): 2:36:36
Business Processes vs. Information Processes: 2:38:28
EER Diagrams: Business Process (Event) Modeling: 2:44:35
DFD Information Process Modeling: 2:46:25
Recording Process DFDs: 2:47:30
General Guidelines for Constructing a DFD: 2:52:00
Maintenance Process DFDs: 2:52:06
Reporting Process DFDs: 2:54:11
REA Modeling Steps: 2:55:22