Database configuration in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the default database engine in Django's settings?

In a new Django project, what database engine is used by default in the DATABASES setting?

Django

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': BASE_DIR / 'db.sqlite3',
    }
}

A SQLite

B MySQL

C PostgreSQL

D Oracle

💡 Hint

Think about the simplest database that requires no extra setup.

Django uses SQLite as the default database engine because it is lightweight and requires no additional installation.

📝 Syntax

intermediate

Identify the syntax error in this Django database configuration

Which option contains a syntax error in the DATABASES setting for PostgreSQL?

Django

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'mydb',
        'USER': 'user',
        'PASSWORD': 'pass',
        'HOST': 'localhost',
        'PORT': '5432'
    }
}

A DATABASES = {'default': {'ENGINE': 'django.db.backends.postgresql', 'NAME': 'mydb', 'USER': 'user', 'PASSWORD': 'pass', 'HOST': 'localhost', 'PORT': '5432'}}

B DATABASES = {'default': {'ENGINE': 'django.db.backends.postgresql', 'NAME': 'mydb', 'USER': 'user', 'PASSWORD': 'pass', 'HOST': 'localhost' 'PORT': '5432'}}

C }}'2345' :'TROP' ,'tsohlacol' :'TSOH' ,'ssap' :'DROWSSAP' ,'resu' :'RESU' ,'bdym' :'EMAN' ,'lqsergtsop.sdnekcab.bd.ognajd' :'ENIGNE'{ :'tluafed'{ = SESABATAD

D DATABASES = {'default': {'ENGINE': 'django.db.backends.postgresql', 'NAME': 'mydb', 'USER': 'user', 'PASSWORD': 'pass', 'HOST': 'localhost', 'PORT': 5432}}

💡 Hint

Look for missing punctuation between keys.

Option B is missing a comma between 'HOST' and 'PORT' keys, causing a syntax error.

❓ state_output

advanced

What will be the database NAME after this settings update?

Given this initial DATABASES setting, what is the value of DATABASES['default']['NAME'] after the update code runs?

Django

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': 'db.sqlite3',
    }
}

# Update to PostgreSQL
DATABASES['default']['ENGINE'] = 'django.db.backends.postgresql'
DATABASES['default']['NAME'] = 'prod_db'
DATABASES['default']['USER'] = 'admin'

A 'prod_db'

B null

C 'db.sqlite3'

D '' (empty string)

💡 Hint

The update changes the NAME key after initial assignment.

The code assigns 'prod_db' to DATABASES['default']['NAME'], so that is the final value.

🔧 Debug

advanced

Why does this Django project fail to connect to the database?

This Django DATABASES setting causes a connection failure. What is the most likely cause?

Django

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'mydb',
        'USER': 'root',
        'PASSWORD': 'password',
        'HOST': '',
        'PORT': '',
    }
}

A Missing 'OPTIONS' key with SSL settings causes failure.

B Empty 'HOST' and 'PORT' cause Django to fail connecting to MySQL server.

C Using 'django.db.backends.mysql' requires installing a MySQL driver which might be missing.

D The 'NAME' key must be a full file path for MySQL connections.

💡 Hint

Check if the database driver is installed and compatible.

Django requires a MySQL driver like mysqlclient or PyMySQL installed to connect using 'django.db.backends.mysql'. Without it, connection fails.

🧠 Conceptual

expert

How does Django handle multiple databases in settings?

If you configure multiple databases in Django's DATABASES setting, how does Django decide which database to use for a model by default?

A Django uses the first database listed in the <code>DATABASES</code> dictionary for all models.

B Django randomly picks one of the configured databases for each query.

C Django requires specifying the database in each model's Meta class to select it.

D Django uses the database named 'default' for all models unless routing is customized.

💡 Hint

Think about the meaning of the 'default' key in the DATABASES setting.

Django uses the 'default' database for all operations unless a database router is implemented to direct queries elsewhere.