BitWithBite
SQL Worksheet
🗃 Data Types & Constraints
SCORE___ / 20
NameClassDate
After this worksheet you can
Pick INT, VARCHAR, DATE, DECIMALUse NOT NULL and UNIQUEUnderstand PRIMARY KEYUse AUTO_INCREMENT📚 Quick Recap
The data types you choose when designing a table affect storage size, query performance, and data integrity. Choosing VARCHAR(255) for every column wastes space. Choosing INT for a phone number loses leading zeros. This lesson teaches you the right type for every situation and how constraints enforce data rules automatically.
🧠 Section A · Concept Check ● BEGINNER 4 × 1 = 4
1Whole numbers use:
2Short text like names uses:
3A PRIMARY KEY must be:
4Money is safest as:
🧮 Section B · Problem Solving ● INTERMEDIATE 2 + 3×3 = 11
5Dates use the type.
6 NULL forbids empty values.
7Choose types for: id, name, price, created_at.
8Why DECIMAL for money instead of FLOAT?
9Write a column definition for a required unique email.
🚀 Section C · Challenge ● CHALLENGE 5
10What happens inserting a duplicate primary key?
💭 Reflection — the most useful thing I learned:
A ___/4 B ___/11 C ___/5 Total ___/20
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✂ answer key — fold or cut before handing out
1-A 2-B 3-A 4-B | 5 DATE 6 NOT 7 = INT, VARCHAR(100), DECIMAL(10,2), DATETIME/DATE 8 = FLOAT rounds; DECIMAL is exact 9 = email VARCHAR(255) NOT NULL UNIQUE | 10 = The insert fails with an error