FAQ: Bases de Datos y modelosLink to this heading#

¿Cómo puedo ver las consultas SQL plano que Django está ejecutando?Link to this heading#

Make sure your Django DEBUG setting is set to True. Then, just do this:

>>> from django.db import connection
>>> connection.queries
[{'sql': 'SELECT polls_polls.id, polls_polls.question, polls_polls.pub_date FROM polls_polls',
'time': '0.002'}]

connection.queries is only available if DEBUG is True. It’s a list of dictionaries in order of query execution. Each dictionary has the following:

``sql`` -- The raw SQL statement
``time`` -- How long the statement took to execute, in seconds.

connection.queries includes all SQL statements – INSERTs, UPDATES, SELECTs, etc. Each time your app hits the database, the query will be recorded.

If you are using multiple databases, you can use the same interface on each member of the connections dictionary:

>>> from django.db import connections
>>> connections['my_db_alias'].queries

If you need to clear the query list manually at any point in your functions, just call reset_queries(), like this:

from django.db import reset_queries
reset_queries()

¿Puedo usar Django con una base de datos ya existente?Link to this heading#

Yes. See Integrating with a legacy database.

Si hago cambios en un modelo, ¿cómo actualizo la base de datos?Link to this heading#

Take a look at Django’s support for schema migrations.

If you don’t mind clearing data, your project’s manage.py utility has a flush option to reset the database to the state it was in immediately after migrate was executed.

¿Django soporta modelos de múltiples columnas en llaves primarias?Link to this heading#

No. Sólo son soportadas llaves primarias de columna única.

But this isn’t an issue in practice, because there’s nothing stopping you from adding other constraints (using the unique_together model option or creating the constraint directly in your database), and enforcing the uniqueness at that level. Single-column primary keys are needed for things such as the admin interface to work; e.g., you need a simple way of being able to specify an object to edit or delete.

¿Soporta Django bases de datos NoSQL?Link to this heading#

NoSQL databases are not officially supported by Django itself. There are, however, a number of side project and forks which allow NoSQL functionality in Django, like Django non-rel.

También puedes echar un vistazo en la “página Wiki’_ que discute algunas alternativas.

How do I add database-specific options to my CREATE TABLE statements, such as specifying MyISAM as the table type?Link to this heading#

We try to avoid adding special cases in the Django code to accommodate all the database-specific options such as table type, etc. If you’d like to use any of these options, create a migration with a RunSQL operation that contains ALTER TABLE statements that do what you want to do.

Por ejemplo, si está usando MySQL y quiere que sus tablas usen el tipo de tabla MyISAM, use la siguiente sentencia SQL:

ALTER TABLE myapp_mytable ENGINE=MyISAM;