Key Concepts of Information Systems: Entities, DML, and Advantages
Key Concepts of Information Systems
1. Entity-Relationship (ER) Model
The Entity-Relationship (ER) model is based on a perception of the real world, consisting of basic objects called entities and the relationships between them.
An Entity is an object distinguishable from other objects by a specific set of attributes.
2. Register-Based Logical Models
Register-based logical models describe data in conceptual and physical models. These models 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) 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 information without changing the whole system.
- Reliability and Availability: Failures are usually local, and the system admits 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 Information Systems
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 implementation and use (Strategic Systems)
8. Transactional Information Systems
These systems often result in significant manpower savings.
- They are usually the first type of IS implemented in organizations.
- They involve intensive input and output of information, with calculations and processes that are 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, and general accounting.
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 are usually developed within the organization and cannot be easily adapted to commercially available packages.
- The typical mode of development is based on increments and 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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