Guides
19 guides on erd. Practical writing from the team building Atlas, useful whether or not you buy anything.
A database diagram is only useful if it matches the real schema. The best ERD tools make it fast to draw entities and relationships and cheap to keep them honest as the database evolves.
Analytical databases are modeled differently from transactional ones. Dimensional modeling (fact tables surrounded by dimensions) is built for fast, understandable analytics, and it has its own diagram shape.
Data modeling is the developer skill that pays off every day and gets taught almost never. This guide covers the practical core: the concepts that make your schemas clean and your queries sane.
You have inherited a database with a hundred tables and no documentation. Reverse-engineering it into a diagram is how you turn an opaque schema into a map you can actually navigate.
DBML lets you describe a database in a few readable lines of text and get an ERD from it. It is diagram-as-code for schemas, and this guide covers the syntax and the workflow.
An ER diagram and a UML class diagram can look almost identical (boxes with fields, lines between them) yet they answer different questions. Knowing which to reach for saves confusion.
A correct schema diagram nobody can read is a failure. The skill is not just showing every table and key, but laying them out so the structure is obvious at a glance.
The same relationship can be drawn three different ways depending on the notation. Knowing crow's foot, Chen, and UML lets you read any ER diagram and choose the clearest for your audience.
Normalization sounds like theory, but it is really about one practical goal: store every fact exactly once. Seeing it on a diagram turns the abstract rules into obvious moves.
Your SQL DDL already defines every table, key, and constraint. Turning CREATE TABLE statements into an ERD is a translation exercise, and this guide gives you the mapping.
Your Prisma schema already describes every entity and relationship in your database. Turning it into an ERD is less about drawing and more about translating what the schema already says.
A good database schema is invisible: it just works, for years, as the application grows. A bad one leaks into every query and migration. This guide is about getting it right early.
An entity relationship diagram turns a fuzzy idea of your data into a precise picture of entities, keys, and relationships. This guide walks through making one from scratch.
DBML is a concise text language for defining database schemas that render as diagrams. This guide covers its syntax for tables, references, enums, and indexes with working examples.
A Prisma schema is already a precise data model in text. This guide shows how to read its models and relations and turn them into a clear entity relationship diagram.
The fastest way to learn ER modeling is to study real examples. This guide walks through three annotated schemas, a blog, an e-commerce store, and a SaaS app, and the decisions behind each.
An existing database already contains a complete data model in its SQL. This guide shows how to read DDL and turn tables, keys, and constraints into a clear entity relationship diagram.
Crow's foot notation is the most widely used way to express cardinality in ERDs. This reference decodes every symbol so you can read and draw any relationship line with confidence.
An entity relationship diagram is the blueprint of a database before it exists. This guide covers entities, attributes, relationships, and cardinality, and how to turn a diagram into a real schema.
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