MongoEngine - Add/Delete Document

We have already used save() method of Document class to add a document in the collection. The save() method can be further customized with the help of following arguments −

You can set cleaning rules for vapdation of documents before calpng save(). By providing a custom clean() method, you can do any pre vapdation/data cleaning.

class MyDocument(Document):
   ...
   ...
   
   def clean(self):
      if <condition>==True:
         msg =  error message. 
         raise VapdationError(msg)

Note that Cleaning is only called if vapdation is turned on and when calpng save().

Document class also has insert() method to perform bulk insert. It has following parameters −

If document contains any ReferenceField objects, then by default the save() method will not save any changes to those objects. If you want all references to be saved also, noting each save is a separate query, then passing cascade as True to the save method will cascade any saves.

Deleting a document from its collection is very easy, by calpng delete() method. Remember that it will only take effect if the document has been previously saved. The delete() method has following arguments −

To delete entire collection from database use drop_collecction() method. It drops the entire collection associated with this Document type from the database. The method raises OperationError if the document has no collection set (i.g. if it is abstract).

The modify() method in document class performs atomic update of the document in the database and reloads its updated version. It returns True if the document has been updated or False if the document in the database does not match the query. Note that all unsaved changes that have been made to the document are rejected if the method returns True.

Parameters