Databases Reference
In-Depth Information
CHAPTER 3
Creating, Updating, and
Deleting Documents
This chapter covers the basics of moving data into and out of the database, including
the following:
• Adding new documents to a collection
• Removing documents from a collection
• Updating existing documents
• Choosing the correct level of safety versus speed for all of these operations
Inserting and Saving Documents
Inserts are the basic method for adding data to MongoDB. To insert a document into
a collection, use the collection's
insert
method:
> db.foo.insert({"bar" : "baz"})
This will add an
"_id"
key to the document (if one does not already exist) and save it
to MongoDB.
Batch Insert
If you have a situation where you are inserting multiple documents into a collection,
you can make the insert faster by using batch inserts. Batch inserts allow you to pass
an array of documents to the database.
Sending dozens, hundreds, or even thousands of documents at a time can make inserts
significantly faster. A batch insert is a single TCP request, meaning that you do not
incur the overhead of doing hundreds of individual requests. It can also cut insert time
by eliminating a lot of the header processing that gets done for each message. When
an individual document is sent to the database, it is prefixed by a header that tells the
