Part 9: Character Data Types: CHAR, VARCHAR, TEXT & Collation

Storing textual data requires understanding string length constraints, memory padding, and character encodings.

1. String Types Comparison

• CHAR(n): Fixed length. If you store 'CA' in CHAR(5), the database pads it with 3 spaces ('CA '). Ideal for fixed codes (e.g. ISO Country Codes CHAR(2)).
• VARCHAR(n): Variable length with a maximum limit n. Stores only the actual characters plus 1–2 length bytes. Ideal for names, emails, titles.
• TEXT: Unlimited variable length (up to 1GB in Postgres). Ideal for blog articles, descriptions, comments.

2. Character Sets & Collation

• Character Set (e.g. utf8mb4): Dictates which characters can be stored (including full emoji support).
• Collation (e.g. utf8mb4_unicode_ci): Dictates how strings are compared and sorted:
• _ci: Case-Insensitive ('Apple' equals 'apple').
• _cs: Case-Sensitive ('Apple' does NOT equal 'apple').

Key Takeaways

• Use CHAR(n) for fixed-length codes.
• Use VARCHAR(n) for standard bounded text inputs.
• Use utf8mb4 encoding to support all international characters and emojis.

In Part 10, we will examine Date, Time & Timestamp Data Types with Timezone Handling!