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Draw an ERD
Create an entity-relationship diagram for a booking system.
Normalise a Flat Dataset
Take a denormalised spreadsheet and normalise it to 3NF.
Data Dictionary for a System Migration
Build a data dictionary for migrating a legacy HR system.
Business Data Modeling & Entity Relationship Diagrams (ERD)
Data modeling structures organizational information logically to support system design. Business analysts create Conceptual and Logical Data Models, Entity Relationship Diagrams (ERDs) using Crow's Foot notation, cardinality mappings (1:1, 1:N, M:N), and data dictionaries.
1. Business Entity Relationship Diagram (ERD)
ERD diagram using Crow's Foot notation illustrating entities, attributes, primary/foreign keys, and cardinalities.
2. Conceptual & Logical Data Model Spec
Documentation detailing business entity definitions, attribute rules, and relational relationships.
3. Data Dictionary & Cardinality Matrix
Data dictionary defining attribute data types, mandatory/optional nullability constraints, and valid domain values.
Frequently Asked Questions (Data Modelling & ERDs)
What is the difference between Conceptual, Logical, and Physical Data Models?
Conceptual models show high-level business entities. Logical models define attributes, keys, and relationships independent of technology. Physical models specify actual database implementation details (table names, indexes, SQL data types).
What do Crow's Foot notation cardinality symbols mean?
Symbols indicate relationship bounds: One (||), Many (>|), Zero (O). Common relationships include 1:1 (One-to-One), 1:N (One-to-Many), and M:N (Many-to-Many).
How do you resolve a Many-to-Many (M:N) relationship in data modeling?
Decompose the M:N relationship into two 1:N relationships by introducing an intermediate associative junction entity (e.g. Student_Courses junction table).
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