ER model

Learn the Entity-Relationship model.

The ER model maps real-world entities and their relationships. Each entity becomes a table, each attribute a column.

-- Varlık: customers
-- İlişki: orders.customer_id -> customers.id

Entity and relationship form the skeleton of data.

ER model — details

The designer first spots entities, then adds attributes, last draws relationships. The diagram lets you see the design before writing tables.

Create the customers table with id, name, email columns. id is the primary key.

Show example solution

CREATE TABLE customers (
  id SERIAL PRIMARY KEY,
  name TEXT NOT NULL,
  email TEXT
);

Create a table for the entity

CREATE TABLE customers (____)

Show answer

CREATE TABLE customers (id SERIAL PRIMARY KEY)

Next lesson: Cardinality