Schema

✅ Schema

define database structure and constraints
logical representation of data
shows how data in DB should be stored logically

• attribute: characteristic of entity
• entity: collection of attribute
• relation: relation between entity

✔️ physical database schema

• how data is stored physically in DB

✔️ logical database schema

• logical constraints
• how data is stored in form of tables
• how tables are connected
• ER modeling

✔️ view database schema

• view level design
• interaction between user and DB
• how to shouw data to user