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Entity–relationship model

lastmod 2026-07-27created 2015-03-129 edits

In the field of data modeling, the entity-relationship model is a set of representations of structured data.

Databases are used to store "structured" data. The "structure" of this data and its accompanying constraints can be designed using various techniques. One of these techniques is Entity-Relationship Modelling, abbreviated ERM. The output of the ERM process is called an Entity-Relationship Diagram, abbreviated ERD. The data modeling process requires a notation to represent the data model as a diagram. An ERD is a type of conceptual data model or semantic data model.

Entity-relationship diagram

ERD [pronounced E-R-D] is a rough, upper-level data diagram often used in strategic or top-down planning. Top-down data planning identifies the entities involved in running an enterprise and determines the relationships among them. Running a business efficiently requires a certain amount of data; this data does not have to involve computers, but computers help greatly in delivering accurate data precisely to those who need it. The data in question needs to be orderly and described in detail, so data about the data is needed for this. Data about data is commonly called metadata, and data models contain such metadata.

Projects

  • samchon/prisma-markdown - ERD and description document auto-generator for Prisma ORM
    • Markdown generator of Prisma, including ERD and descriptions
    • Reads Prisma ORM schema files and automatically generates ERDs and description documents
    • ERDs are generated as mermaid diagrams
    • Descriptions are built by reading Prisma ORM comments
    • Even hundreds or thousands of tables can be represented using page splitting

Design Tools

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author Zer0 sitemap