Table Design Best Practices

Good table design prevents future pain.

A few disciplined choices now can save many migrations, bug fixes, and data cleanup scripts later.

Core Concepts

flowchart LR
  A[Identify entities] --> B[Pick clear keys]
  B --> C[Add required constraints]
  C --> D[Set sane defaults]
  D --> E[Review with real query needs]

Design area	Recommended default	Why
Primary key	INTEGER PRIMARY KEY	Simple, efficient identity
Required fields	NOT NULL	Prevent missing critical values
Business uniqueness	UNIQUE (+ NOT NULL when required)	Prevent duplicates
Validation	CHECK	Keep bad values out
Audit creation time	DEFAULT CURRENT_TIMESTAMP	Consistent row metadata

Do This

• Use descriptive names (customer_id, created_at)
• Keep one fact per column
• Prefer small, explicit constraints
• Use integer ids for most internal keys

Avoid This

• Generic column names (data, misc)
• Comma-separated lists in one column
• Schema with no primary key
• Relying only on app validation

Code Examples

-- Example of a well-structured table for common app data.
CREATE TABLE customers (
  customer_id  INTEGER PRIMARY KEY,
  email        TEXT NOT NULL UNIQUE,
  full_name    TEXT NOT NULL,
  age          INTEGER CHECK (age >= 0),
  created_at   TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
);

Expected output
Table customers created with key constraints and defaults.

-- Verify the final schema text.
SELECT sql
FROM sqlite_schema
WHERE type = 'table' AND name = 'customers';

sql
CREATE TABLE customers (... email TEXT NOT NULL UNIQUE ... CHECK (age >= 0) ...)

SQLite-Specific Nuances

SQLite Nuance

Because SQLite is flexible with typing, schema constraints are even more important for preserving data quality.

Think of constraints as your first line of defense.

Common Pitfalls / Best Practices

Pitfall

Creating tables quickly without constraints and planning to "clean data later".

Data cleanup almost always costs more than prevention.

Best Practice

Before finalizing a table, run this checklist: primary key, required fields, uniqueness, validation, defaults.

Quick Challenge

Design a books table with:

• book_id primary key
• required title
• required + unique isbn
• price must be non-negative
• created_at default timestamp

View Solution

CREATE TABLE books (
  book_id     INTEGER PRIMARY KEY,
  title       TEXT NOT NULL,
  isbn        TEXT NOT NULL UNIQUE,
  price       REAL CHECK (price >= 0),
  created_at  TEXT DEFAULT CURRENT_TIMESTAMP
);

Expected output
Table created with identity, quality constraints, and creation timestamp.