Understanding Information Systems: Key Concepts & Components
Key Concepts of Information Systems
1. Entity-Relationship (ER) Model
The Entity-Relationship (ER) model is based on a perception of the real world that consists of a collection of basic objects called entities and relationships between these objects.
An Entity is an object that is distinguishable from other objects by means of a specific set of attributes.
2. Registration-Based Logical Models
Register-based logical models are used to describe data in conceptual and physical models. They specify the overall logical structure of the database (DB) and provide a higher-level description of the implementation.
3. Data Manipulation Language (DML)
A Data Manipulation Language (DML) is a language that enables users to access or manipulate data organized according to the appropriate data model. There are two types:
- Procedural
- Non-procedural
4. Components
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5. Advantages of Distributed Systems
A distributed system should appear to the user as a centralized system, offering:
- Transparency to the location
- Transparency to fragmentation
- Transparency to replication
Key Advantages:
- Local Autonomy: Each group is responsible for its data. Local treatment is faster.
- Capacity and Incremental Growth: It can address larger-scale projects and extend the information without changing the whole system.
- Reliability and Availability: Failures are usually local, admitting a certain level of redundancy.
- Efficiency and Flexibility
6. Basic Information System Activities
The basic activities of an Information System (IS) are: Entry, Storage, Processing, and Output.
7. Main Tasks of an Information System
An IS satisfies three basic objectives:
- Business Process Automation Systems (Transactional)
- Provide information to support decision-making (Decision Support Systems, DSS)
- Achieving competitive advantage through its implementation and use (Strategic Systems)
8. Transactional Information Systems
- Often result in significant savings of manpower.
- They are usually the first type of IS implemented in organizations.
- They involve intensive input and output of information, with calculations and processes often simple.
- They are collectors of information, loading large databases for later use.
- They are easy to justify to general management, as their benefits are visible and palpable.
- Packages are easily adaptable from what is available in the market.
- Examples include billing, payroll, accounts receivable, accounts payable, general accounting, etc.
9. Strategic Information Systems
- Their primary role is not to support the automation of business processes or provide information to support decision-making, although they can perform those functions.
- They usually develop within the organization and cannot be easily adapted to commercially available packages.
- The typical mode of development is based on increments and through continuous development within the organization.
- Their function is to achieve benefits that competitors do not possess, such as cost advantages and differentiated services to customers and suppliers.
- They support the process of innovation in products and processes within the company.
10. Starting an Information System
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