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Summary - Design

Move from an ER model to table design.

Summary - Design

Database design starts with the ER model, continues with cardinality and key choice. The balance of surrogate and natural keys, and the denormalization call, form the core of design.

-- ER -> tablolar
-- 1:N -> FOREIGN KEY
-- M:N -> junction table

Design steps are sequential.

Practice Summary - Design

Summary task: create the members table with id SERIAL PRIMARY KEY and email TEXT UNIQUE.

Starter code

query.sql
-- summary design
CREATE TABLE members

Sample solution

query.sql
CREATE TABLE members (
  id SERIAL PRIMARY KEY,
  email TEXT UNIQUE
);

Expected output

CREATE TABLE

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Surrogate key type

Question 
id ____ PRIMARY KEY
Answer 
id SERIAL PRIMARY KEY

Explanation: A surrogate key is an automatic number with no business meaning; SERIAL generates it.

2 What table does an M:N relationship require?

  • A procedure
  • A view
  • A trigger
  • A junction table Correct answer

Explanation: An M:N relationship requires a junction table.

3 Summary - Design: match the terms

Term Meaning
ER model
1:N foreign
M:N junction
denormalize merge

All lessons in Expert

1 Database design

  1. ER model
  2. Cardinality
  3. Surrogate keys
  4. Natural keys
  5. Denormalization
  6. Summary - Design

2 Index tuning

  1. B-tree structure
  2. Covering index
  3. Partial index
  4. Index selectivity
  5. Index maintenance
  6. Summary - Index tuning

3 Query optimizer

  1. What is an optimizer?
  2. Statistics
  3. Cost model
  4. Join strategies
  5. Plan cache
  6. Summary - Optimizer

4 Project: Performance tuning

  1. Scenario design
  2. Reading plans
  3. Adding indexes
  4. Rewriting queries
  5. Comparing results

5 Replication and sharding

  1. What is replication?
  2. Master-slave
  3. Sync vs async
  4. What is sharding?
  5. Shard key
  6. Summary - Replication and sharding

6 Distributed and big data

  1. Distributed queries
  2. MPP
  3. Columnar storage
  4. SQL on Hadoop
  5. SQL vs NoSQL
  6. Summary - Distributed and big data

7 Security and backup

  1. SQL injection
  2. Parameterised queries
  3. Authorisation
  4. Backup
  5. Recovery
  6. Summary - Security and backup

8 Expert final

  1. Design challenge
  2. Optimization challenge
  3. Security challenge
  4. Backup challenge