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0 MongoDB – Insert Single Document in a Collection using insertOne()
MongoDB provides the following methods to insert documents into a collection:
- insertOne() – Inserts a single document
- insert () (Deprecated) – Inserts one or more documents
- insertMany() – Insert multiple documents
insertOne()
Syntax:
db.collection.insertOne(document)
The following inserts a document into employees collection.
Example: insertOne()
db.employees.insertOne({
firstName: "John",
lastName: "King",
email: "john.king@abc.com"
})
Output
{
acknowledged: true,
insertedId: ObjectId("616d44bea861820797edd9b0")
}Explanation: We passed a document to the insertOne() method. Notice that we haven’t specified _id field. So, MongoDB inserts a document to a collection with the auto-generated unique _id field. It returns an object with a boolean field acknowledged that indicates whether the insert operation is successful or not, and insertedId field with the newly inserted _id value.
Insert _id Manually
It is not necessary to insert auto-generated _id value. You can manually specify a unique value for the _id field, as shown below.
Example: Insert a Document
db.employees.insertOne({
_id:"1",
firstName: "John",
lastName: "King",
email: "john.king@abc.com"
})
Output
{
acknowledged: true,
insertedId: 1
}
Note that while adding your custom value to _id field, a value must be unique; otherwise, it will throw an error. The following tries to add the same _id value.
Example: Insert a Document
db.employees.insertOne({
_id:"1",
firstName: "John",
lastName: "King",
email: "john.king@abc.com"
})
Output
MongoServerError: E11000 duplicate key error collection: humanResourceDB.employees index: _id_ dup key: { _id: "1" }
Note: MongoDB is NoSQL database. So, it does not enforce schema to any collection. It means you can insert a document with any fields to a collection. For example, the following inserts a document with different fields to the employees collection.
Example: Insert a Document with different column label
db.employees.insertOne({
fName: "John",
lName: "King",
emailid: "john.king@abc.com"
})
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