Field sizes

Tip: Choose Save as PDF in the print dialog to download. Use A4 paper size.

Field sizes

Name:
Date:
Class:
A

Quick Questions

Shade in the A or B circle for each question.

1. A field is set as VARCHAR(30). What does the 30 mean?
A The value can be up to 30 characters long
B The value must be the number 30
2. A State field holds values like 'VIC' and 'NSW'. Which size fits best?
A VARCHAR(3)
B VARCHAR(255)
3. A field is VARCHAR(10). A user enters 'Christopher' (11 characters). What can happen?
A The field grows automatically to fit it
B The value is rejected or cut off to fit
4. Which statement about field sizes is true?
A Every field should use the largest possible size
B Smaller field sizes save storage space
5. Which field definition sets a maximum text length of 50 characters?
A LastName VARCHAR(50)
B LastName VARCHAR[50 characters]
B

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left columnRight column
1firstName VARCHAR(30) AThe postcode field is set to a size of exactly 4 characters
2postcode CHAR(4) ByearLevel TINYINT
3A field size sets the maximum length of text a value may use, so a short code only needs a small size CA size of 10 is too small for most email addresses, so many values would be rejected or cut off.
4A smaller field size saves storage, so a field holding a small whole number can use a small number type DstateCode VARCHAR(3)
5INSERT INTO students (house) VALUES ('Burgundy Dragons'); -- house VARCHAR(5) EThe firstName field can store text up to a maximum of 30 characters
6email VARCHAR(10) FThe value has 16 characters but the field size only allows 5, so it will be rejected or cut off.
C

Definitions

VARCHAR(30)
D

Fill in the Blanks

Complete each line of code by filling in the missing parts.

1.
-- Text of varying length, max 30 firstName _______(30)
2.
-- Names may be up to 30 characters firstName VARCHAR(__)
3.
-- State code, always 3 characters state CHAR(_)
4.
-- Australian postcodes have 4 digits postcode CHAR(_)
5.
-- 6 digits in total, 2 after the point price DECIMAL(_,2)
E

Spot the Error

Shade in the letter of the line that contains an error.

Question 1
A CREATE TABLE students (
B studentId INT,
C firstName VARCHAR[30],
D house VARCHAR(10)
E );
Question 2
A CREATE TABLE products
B name VARCHAR(50),
C price DECIMAL(6,2)
D );
Question 3
A postcode CHAR(four),
B suburb VARCHAR(40),
C state CHAR(3)
Question 4
A -- Houses: Red, Blue, Green
B -- Longest name: 5 characters
C house VARCHAR(3)
Question 5
A -- Smaller sizes save storage
B -- Choose smallest size needed
C -- Y/N flag needs 1 character
D member CHAR(255)

Answer Key

Field sizes
Section A: Quick Questions
Q1
A — The value can be up to 30 characters long
Q2
A — VARCHAR(3)
Q3
B — The value is rejected or cut off to fit
Q4
B — Smaller field sizes save storage space
Q5
A — LastName VARCHAR(50)
Section B: Match the Pairs
Q1
firstName VARCHAR(30) → The firstName field can store text up to a maximum of 30 characters
Q2
postcode CHAR(4) → The postcode field is set to a size of exactly 4 characters
Q3
A field size sets the maximum length of text a value may use, so a short code only needs a small size → stateCode VARCHAR(3)
Q4
A smaller field size saves storage, so a field holding a small whole number can use a small number type → yearLevel TINYINT
Q5
INSERT INTO students (house) VALUES ('Burgundy Dragons'); -- house VARCHAR(5) → The value has 16 characters but the field size only allows 5, so it will be rejected or cut off.
Q6
email VARCHAR(10) → A size of 10 is too small for most email addresses, so many values would be rejected or cut off.
Section C: Definitions
Q1
VARCHAR(30) — Field size sets the maximum length or storage a value may use. VARCHAR(30) allows up to 30 characters; longer values are rejected or cut. Smaller sizes save storage.
Section D: Fill in the Blanks
Q1
-- Text of varying length, max 30 firstName VARCHAR(30)
Q2
-- Names may be up to 30 characters firstName VARCHAR(30)
Q3
-- State code, always 3 characters state CHAR(3)
Q4
-- Australian postcodes have 4 digits postcode CHAR(4)
Q5
-- 6 digits in total, 2 after the point price DECIMAL(6,2)
Section E: Spot the Error
Q1
C — The field size must go in round brackets, not square brackets. It should be VARCHAR(30).
Q2
A — The opening bracket is missing. The field definitions, including their sizes such as VARCHAR(50), must start after CREATE TABLE products (
Q3
A — A field size must be a number inside the brackets. It should be CHAR(4).
Q4
C — 'Green' has 5 characters, so a size of 3 would reject it or cut it to 'Gre'. The size should be VARCHAR(5).
Q5
D — A Y/N flag needs only 1 character. A size of 255 wastes storage. It should be CHAR(1).