Entity Relationship Diagram
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MermaidVisualize how your database pieces fit together. This template maps the relationships between different data entities — showing what information each table holds, how tables connect to each other, and the type of relationships that exist. It's essential for anyone building or documenting databases, helping developers understand data structure, identifying missing connections, or planning migrations.
How to create Entity Relationship Diagram
To create a entity relationship diagram, follow these steps:
01.
Identify entities
Define the main objects or concepts in your system that need to store data (e.g., Customer, Order, Product).
02.
List attributes
For each entity, specify what information it holds, including data types (string, integer, date, etc.).
03.
Mark keys
Identify primary keys (PK) that uniquely identify each record and foreign keys (FK) that reference other tables.
04.
Create entities
Draw rectangles for each entity with attributes listed inside, clearly marking primary and foreign keys.
05.
Define relationships
Determine how entities connect — does a customer place many orders? Does an order contain many products?
06.
Add relationship lines
Draw lines between entities showing connections, using proper cardinality notation (one-to-one, one-to-many, many-to-many).
07.
Review & share
Share the diagram for database development, API planning, data migration projects, or technical documentation.
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