Django connects to an external database through connection parameters defined in the project’s settings.py file. The DATABASES setting in settings.py defines the database connection parameters, including the database type, the name of the database, the username and password for connecting to the database, and other parameters such as the host, port, and charset.
Here’s an example of a DATABASES setting for a PostgreSQL database:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'mydatabase',
'USER': 'mydatabaseuser',
'PASSWORD': 'mypassword',
'HOST': 'localhost',
'PORT': '5432',
}
}
In this example, the ENGINE setting specifies the database backend (PostgreSQL), the NAME setting specifies the database name (mydatabase), while the USER and PASSWORD settings provide the credentials for database access. The HOST and PORT settings specify the host and port of the database server.
The HOST and PORT settings are network-related parameters necessary when connecting to database servers running on a separate machine or a non-standard port. For local database installations (like on localhost), the defaults often work. However, for remote database servers or specific port configurations, these settings are essential to ensure Django can locate and access the database server over the network.
The ENGINE setting is crucial as it tells Django which database backend to use. django.db.backends.postgresql specifically instructs Django to use the PostgreSQL backend. Other possible values for ENGINE include: django.db.backends.mysql for MySQL, django.db.backends.sqlite3 for SQLite, and django.db.backends.oracle for Oracle. Selecting the correct ENGINE ensures Django utilizes the appropriate database driver and connection logic for your chosen database system.
Note: To use databases other than SQLite, you typically need to install the corresponding database driver package (e.g., psycopg2 for PostgreSQL, mysqlclient or mysql-connector-python for MySQL) separately via pip.
Once the database connection is defined in the settings.py file, you can use Django’s ORM to interact with the database, including querying data, inserting data, updating data, and deleting data.
Testing the Database Connection
After configuring your database settings, it is crucial to verify that Django can successfully connect to your database. You can test the connection by running Django management commands that interact with the database, such as python manage.py migrate or python manage.py check.
If the connection is successful, these commands will execute without errors. If there are connection issues, Django will typically raise exceptions indicating the nature of the problem, such as database connection refused, invalid credentials, or missing database drivers. Carefully review any error messages to troubleshoot connection problems.