Schema builder (columns, types) in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Laravel migration column definition?

Consider this Laravel migration snippet:

Schema::create('products', function (Blueprint $table) {
  $table->string('name', 100);
  $table->decimal('price', 8, 2);
  $table->timestamps();
});

What will be the SQL column types generated for name and price?

Laravel

Schema::create('products', function (Blueprint $table) {
  $table->string('name', 100);
  $table->decimal('price', 8, 2);
  $table->timestamps();
});

A name: VARCHAR(255), price: DOUBLE

B name: TEXT, price: FLOAT

C name: VARCHAR(100), price: DECIMAL(8,2)

D name: CHAR(100), price: DECIMAL(10,2)

💡 Hint

Look at the parameters passed to string() and decimal() methods.

The string() method with a length parameter creates a VARCHAR column with that length. The decimal() method creates a DECIMAL column with precision and scale as specified.

📝 Syntax

intermediate

Which option correctly defines a nullable integer column in Laravel schema?

You want to add an integer column named age that can be empty (nullable). Which of these Laravel schema builder lines is correct?

A $table->integer('age')->nullable();

B $table->integer('age')->null();

C $table->integer('age', true);

D $table->nullable()->integer('age');

💡 Hint

Check the method chaining order and method names.

The nullable() method is called after defining the column type to allow NULL values. The other options either use wrong method names or wrong order.

🔧 Debug

advanced

Why does this Laravel migration code cause an error?

Examine this migration snippet:

Schema::table('users', function (Blueprint $table) {
  $table->string('email')->unique()->nullable(false);
});

Why will this cause an error or unexpected behavior?

Laravel

Schema::table('users', function (Blueprint $table) {
  $table->string('email')->unique()->nullable(false);
});

A unique() must come after nullable(), order matters

B nullable(false) is invalid; nullable() only accepts no arguments or true

C string() requires a length parameter, missing here

D You cannot add unique constraint in a table modification

💡 Hint

Check the nullable() method signature in Laravel schema builder.

The nullable() method does not accept any arguments. Passing false causes a syntax error or unexpected behavior. To make a column NOT nullable, omit nullable() or use ->nullable(false) is invalid.

❓ state_output

advanced

What is the default value of a boolean column defined like this in Laravel?

Given this migration code:

Schema::create('settings', function (Blueprint $table) {
  $table->boolean('active');
});

What will be the default value of the active column if no default is set explicitly?

Laravel

Schema::create('settings', function (Blueprint $table) {
  $table->boolean('active');
});

A true (1)

B false (0)

C NULL

D No default, insert will fail without value

💡 Hint

Think about how databases handle columns without defaults and NOT nullable.

By default, boolean columns are NOT nullable and have no default value. So inserting a row without specifying 'active' will cause an error.

🧠 Conceptual

expert

Which Laravel schema builder column type should you use for storing large JSON data efficiently?

You want to store large JSON data in a database column using Laravel's schema builder. Which column type is best suited for this purpose?

A $table->jsonb('data');

B $table->text('data');

C $table->json('data');

D $table->longText('data');

💡 Hint

Consider database support for JSON types and efficiency.

The jsonb type stores JSON data in a binary format, allowing indexing and efficient querying, supported in PostgreSQL. json() stores JSON as text without indexing. text() and longText() store plain text without JSON features.

Practice

1. What does the Schema::create method do in Laravel migrations?

easy

A. Creates a new database table with specified columns

B. Deletes an existing database table

C. Updates data inside a table

D. Runs raw SQL queries directly

Solution

1. Step 1: Understand the purpose of Schema::create

   This method is used to define a new table structure in the database.

2. Step 2: Recognize the role of columns inside the callback

   The callback function receives a Blueprint object to define columns for the new table.

3. Final Answer:

   Creates a new database table with specified columns -> Option A

4. Quick Check:

   Schema::create = create table [OK]

Hint: Schema::create always defines a new table [OK]

Common Mistakes:

• Confusing create with drop or update
• Thinking it modifies data instead of structure
• Assuming it runs raw SQL

2. Which of the following is the correct syntax to add a string column named title in a Laravel migration?

easy

A. $table->varchar('title');

B. $table->string('title');

C. $table->text('title');

D. $table->char('title');

Solution

1. Step 1: Identify the correct method for string columns

   Laravel uses string() to create VARCHAR columns.

2. Step 2: Check the syntax for adding a column

   The syntax is $table->string('column_name'); which matches $table->string('title');.

3. Final Answer:

   $table->string('title'); -> Option B

4. Quick Check:

   String column = $table->string('name') [OK]

Hint: Use $table->string() for VARCHAR columns [OK]

Common Mistakes:

• Using varchar() which does not exist
• Confusing text() with string()
• Using char() without length

3. What will be the resulting column type in the database for this migration code?

$table->integer('age')->unsigned();

medium

A. Unsigned integer column

B. Signed integer column

C. String column named 'age'

D. Boolean column

Solution

1. Step 1: Understand the integer() method

   This creates an integer type column in the database.

2. Step 2: Analyze the effect of unsigned()

   The unsigned() modifier makes the integer only accept positive values (no negatives).

3. Final Answer:

   Unsigned integer column -> Option A

4. Quick Check:

   integer()->unsigned() = unsigned int [OK]

Hint: unsigned() means no negative numbers allowed [OK]

Common Mistakes:

• Ignoring unsigned modifier
• Thinking integer() creates string
• Confusing with boolean type

4. Identify the error in this migration code snippet:

Schema::create('users', function (Blueprint $table) {
    $table->string('email')->nullable;
});

medium

A. String columns cannot be nullable

B. Wrong method name, should be allowNull()

C. Blueprint object is not imported

D. Missing parentheses after nullable method

Solution

1. Step 1: Check the nullable method usage

   In Laravel, nullable is a method and must be called with parentheses ().

2. Step 2: Identify the missing parentheses

   The code uses nullable without (), causing a syntax error.

3. Final Answer:

   Missing parentheses after nullable method -> Option D

4. Quick Check:

   nullable() requires parentheses [OK]

Hint: Always add () after nullable method [OK]

Common Mistakes:

• Writing nullable without ()
• Using allowNull() instead of nullable()
• Assuming string can't be nullable

5. You want to create a table with a primary key id that auto-increments, a nullable description text column, and a price decimal column with 8 digits total and 2 decimal places. Which migration code is correct?

hard

A. Schema::create('products', function (Blueprint $table) { $table->bigIncrements('id'); $table->text('description'); $table->decimal('price', 8, 2); });

B. Schema::create('products', function (Blueprint $table) { $table->integer('id')->autoIncrement(); $table->string('description')->nullable; $table->decimal('price', 8); });

C. Schema::create('products', function (Blueprint $table) { $table->increments('id'); $table->text('description')->nullable(); $table->decimal('price', 8, 2); });

D. Schema::create('products', function (Blueprint $table) { $table->increments('id'); $table->text('description')->nullable; $table->decimal('price', 8, 2); });

Solution

1. Step 1: Check primary key and auto-increment

   $table->increments('id') creates an auto-incrementing primary key integer column.

2. Step 2: Verify nullable text column syntax

   $table->text('description')->nullable(); correctly makes the text column nullable with parentheses.

3. Step 3: Confirm decimal column precision

   $table->decimal('price', 8, 2); defines a decimal with 8 digits total and 2 decimal places.

4. Final Answer:

   Schema::create('products', function (Blueprint $table) { $table->increments('id'); $table->text('description')->nullable(); $table->decimal('price', 8, 2); }); -> Option C

5. Quick Check:

   increments + nullable() + decimal(8,2) = correct [OK]

Hint: Use increments() for PK, nullable() with (), decimal needs precision [OK]

Common Mistakes:

• Forgetting parentheses on nullable()
• Using autoIncrement() instead of increments()
• Missing decimal precision arguments