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INFO MANAGEMENT L3
Entity Relationship Modeling
| Question | Answer |
|---|---|
| a conceptual model for designing a databases. This model represents the logical structure of a database, including entities, their attributes and relationships between them. | The Entity-Relationship Model (ER Model) |
| a conceptual approach to designing databases by identifying the entities, attributes, and relationships between data objects. It provides a visual blueprint of how data interacts within a system before actual database creation. | Entity Relationship Modeling (ER Modeling) |
| Purpose of ER Modeling: | To help analyze and structure data To serve as a communication tool between developers To create a foundation for relational database design |
| A person, place, thing, or event that an organization wants to store data about. | Entity |
| A characteristic or property of an entity. | Attribute |
| An association between two or more entities. | Relationship |
| defines how many instances of one entity are related to instances of another entity. | Cardinality |
| Unique identifiers that distinguish records | Keys |
| uniquely identifies each entity | Primary Key |
| links related entities | Foreign Key |
| Examine the business requirements (rules) to identify the main nouns or concepts about which data must be stored | Identify Entities (The Nouns) |
| Define the attributes (data fields) that describe each entity | Define Attributes (The Properties) |
| The resulting ER Diagram visually confirms the database structure. | Establish Relationships and Cardinality (The Verbs and Rules) |
| Shows how entities and relationships CONNECT IN AN EASY TO UNDERSTAND DIAGRAM. Helps both technical and non-technical users visualize database structure. | Clear Data Visualization |
| Acts as a common language between system analysts, developers, and end-users. Ensures everyone understands how DATA FLOWS THROUGH THE SYSTE, | Improves Communication |
| Identifies entities, attributes, and relationships BEFORE IMPLEMENTATION. Minimizes data redundancy and ensures consistency | Efficient and Accurate Design |
| DETECT THE DESIGN ISSUE early in the planning stage, saving time and effort. | Early Error Detection |
| ER Models can be systematically converted into relational database tables | Easy Transition to Database |
| ER Models describe what data exists, not how it is processed or used. Cannot show workflows or system behavior. | Focuses Only on Structure |
| Poor at capturing complex rules (e.g., time-based conditions or business constraints).Such logic must be handled by the application layer. | Limited Expressiveness |
| Diagrams become cluttered and hard to interpret when too many entities exist. | Complexity in Large Systems |
| Different designers may model the same system differently (Entity vs. Attribute confusion). | Subjective Design Choices |
| Works best for structured, relational databases — not for big data, multimedia, or NoSQL systems. | Not Ideal for Unstructured Data |