# Accessing the database directly
# Working with collections
A good example is updating one document property, like a "view counter" of a blog article. Everyone can see the page, so you don't care about permissions. You don't need to update the entire document object. You just want to update one small piece of it.
Here is an example of how to do that in a piece. We will override the
beforeShow() method of the
@apostrophecms/piece-page-type. This method lets us make modifications just before the
show.html of the associated
@apostrophe/piece-page-type is displayed to the user.
beforeShow() method we are gaining access to the
aposDocs collection of the project database using
self.apos.doc.db. This reference to the collection is shorthand for
self.apos.db.collection('aposDocs'). Note that this is not the same thing as
self.apos.db, which is the main MongoDB connection object.
There are references to other core apostrophe collections that can be accessed in this same way through
self.apos.<xxx>.db. For example,
self.apos.attachment.db gives access to CRUD (Create, Read, Update, Delete) operations on the
aposAttachments collection. Note that the reference uses the singular version of the name.
Next, we are invoking a method of the MongoDB collection saying that we want to update one document within the database. You can read about other methods within the MongoDB Node.js driver docs (opens new window).
We are passing two arguments to the MongoDB method. The first is a MongoDB criteria object which ensures our query only matches the document with the desired
_id. MongoDB objects always have an
_id property, a unique identifier that can always be used to find that specific document.
The second argument is an object which passes a MongoDB operator
$inc set to the name and value of the field we want to alter. In this case, incrementing the
views field by 1. This could then be accessed in the
show.html template for the
Keep in mind, this update to the record happened after the requested piece was already returned from the database because we used the
beforeShow() method. So, if five people had looked at that blog article previously,
data.piece.views in the template would be equal to 5 for the duration of the current request, but the database record views would now be 6 due to our
In addition to the
$inc operator, there are a number of other MongoDB operators where it makes sense to access database directly. This includes
$unset. You can read more about their usage in the MongoDB documentation (opens new window).
These same methods of altering documents outside of the Apostrophe model layer can be used in tasks created by any module. As examples, the Apostrophe modules expose multiple tasks like adding users through
node app @apostrophecms/user:add <name> <role> from the
@apostrophecms/user module or completely resetting your database (dangerous!) through
node app @apostrophecms/db:reset.
# Making your own database connections
While the core of apostrophe depends on connections to MongoDB through the mongodb native module, that doesn't mean that your custom modules are limited in the same way. If you feel like using Mongoose, go ahead! If you want to use a different database, why not!
Just install the packages you need and invoke the functions of the appropriate library with
await within the
async init(self) function of your module. Then attach the returned connection object to a property of
self, granting access to it later in any method, handler, route, etc. of the module. You should also clean up such connections in an