MongoDB provides the
insert() method (and two others) for adding documents to a database.
MongoDB provides the following three methods for inserting documents into a database:
insert()insertOne()insertMany()
The insert() Method
The
insert() method inserts one or more documents into a collection. Each document is provided as a parameter. The collection name is prepended to the insert() method.
Here's the syntax for inserting a single document:
In the above example, the document consists of
{ name: "value" }. This is a JSON document. JSON documents consist of one or more name/value pairs, enclosed in curly braces {}.
MongoDB uses JSON documents to store data, so that's why we insert documents in this format.
We've already used this method previously when we created a database.
Let's add another document to our database:
This inserts a document with
{ artistname: "Jorn Lande" } as its contents.
Now, if we search the artists collection, we will see two documents (including the one we created previously):
> db.artists.find()
{ "_id" : ObjectId("5780fbf948ef8c6b3ffb0149"), "artistname" : "The Tea Party" }
{ "_id" : ObjectId("5781c9ac48ef8c6b3ffb014a"), "artistname" : "Jorn Lande" }
Note that MongoDB has created an
_id field for the documents. If you don't specify one, MongoDB will create one for you. However, you can provide this field when doing the insert if you prefer to have control over the value of the _id field.
Result:
> db.artists.find()
{ "_id" : ObjectId("5780fbf948ef8c6b3ffb0149"), "artistname" : "The Tea Party" }
{ "_id" : ObjectId("5781c9ac48ef8c6b3ffb014a"), "artistname" : "Jorn Lande" }
{ "_id" : 1, "artistname" : "AC/DC" }
The
_id that MongoDB provides is a 12-byte ObjectId value. It is made up of the following values;- a 4-byte value representing the seconds since the Unix epoch,
- a 3-byte machine identifier,
- a 2-byte process id, and
- a 3-byte counter, starting with a random value.
Create Multiple Documents
You can insert multiple documents within a single
insert() method.
In this example, we insert three documents:
Note that the documents are provided as an array. The documents are enclosed in square brackets
[], and they are separated by commas.
Running the above code results in the following message:
BulkWriteResult({
"writeErrors" : [ ],
"writeConcernErrors" : [ ],
"nInserted" : 3,
"nUpserted" : 0,
"nMatched" : 0,
"nModified" : 0,
"nRemoved" : 0,
"upserted" : [ ]
})
Embedded Documents
A document can contain other documents, arrays, and arrays of documents.
You can also provide multiple name/value pairs within a document by separating them with a comma.
Result:
WriteResult({ "nInserted" : 1 })
Parameters
The
insert() method accepts the following parameters.| Parameter | Type | Description |
|---|---|---|
document | document or array | A document or array of documents to insert into the collection (as in the above examples). |
writeConcern | document | Optional parameter. This is a document expressing the write concern. A write concern describes the level of acknowledgement requested from MongoDB for write operations to a standalone mongod or to replica sets or to sharded clusters. |
ordered | boolean | Optional parameter. If the value is set to true, MongoDB will perform an ordered insert of the documents in the array, and if an error occurs with one of documents, MongoDB will return without processing the remaining documents in the array.
If the value is set to
false, MongoDB will perform an unordered insert, and if an error occurs with one of documents, the remaining documents in the array will continue to be processed. |
The insertOne() Method
You can also use the
insertOne() method to insert a single document into a collection:
Here, we've specified a non-existent collection. As with the
insert() method, the specified collection will be created if it doesn't already exist.
You'll notice that the output is different to when you use the
insert() method:{ "acknowledged" : true, "insertedId" : 1 }
Embedded Documents
As with
insert(), you can insert embedded documents and arrays of documents:
Result:
{
"acknowledged" : true,
"insertedId" : ObjectId("578214f048ef8c6b3ffb0159")
}
The insertMany() Method
As the name suggests, you can use
insertMany() to insert multiple documents:
Again, the output when using
insertMany() is different than if you'd inserted multiple documents using the insert() method:{
"acknowledged" : true,
"insertedIds" : [
2,
3,
4,
5,
6,
7,
8
]
}
Embedded Documents
Result:
{
"acknowledged" : true,
"insertedIds" : [
ObjectId("578217c248ef8c6b3ffb015a"),
ObjectId("578217c248ef8c6b3ffb015b")
]
}
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