MongoDB insertMany() Method (original) (raw)

Last Updated : 5 May, 2026

insertMany() inserts multiple documents in one operation, improving performance and efficiency.

• Adds many documents at once.
• Can be more efficient than single inserts depending on batch size, network conditions, and workload.
• Efficient for large datasets.

**Syntax:

db.collection_name.insertMany([<document 1>, <document 2>, ...],{writeConcern: ,ordered: })

• ****, , … :** Array of documents to insert.
• **writeConcern (optional): Overrides the default write concern.
• **ordered (optional): true inserts in order (default); set false for unordered inserts.

Return Type of insertMany()

The insertMany() method returns an object that includes:

• **acknowledged: A boolean that is true if the write concern was enabled, and false if it was disabled.
• **insertedIds: An object containing the _id values of the inserted documents.

Examples of Using insertMany() in MongoDB

We’ll assume we’re working with a collection called student, which contains information about students such as their name and age.

Example 1: Insert Multiple Documents in a Single Operation without Specifying an _id field

We insert the array of documents that contains the name and age of the students.

**Query:

db.student.insertMany([{name:"Ryan",age:20}, {name:"Ron",age:24}, {name:"Kim",age:26}])

**Output:

Three documents are inserted into the student collection in a single operation.

Example 2: Insert Several Documents Specifying an _id Field

The query inserts multiple documents with custom _id values into the student collection, and MongoDB throws a duplicate key error if any _id already exists.

**Query:

db.student.insertMany([{ _id: "stu200", name: "Luca", age: 20 }, { _id: "stu201", name: "Tim", age: 24 }])

**Output:

The documents are inserted successfully with the given _id, preventing automatic ObjectId generation. If _id is duplicated, MongoDB will reject the insert operation for that document.

Error Handling

During bulk operations like insertMany(), MongoDB may throw a BulkWriteError (e.g., due to duplicate _id values), which can be handled using a try–catch block in application code.

• **Duplicate Key Errors: Ensure no duplicates in unique indexed fields, and use { ordered: false } to continue inserting remaining documents despite errors.
• **Validation Errors: Ensure all documents meet schema validation rules.
• **Network Issues: Implement retry logic to handle transient network errors.
• **Error Handling: Examine error details to understand and address specific issues.

var docs = [ /* array of documents */ ]
db.collection.insertMany(docs, { ordered: false })
.then(result => console.log(result))
.catch(error => {
if (error.name === "BulkWriteError") {
error.writeErrors.forEach(writeError => {
console.error("Document index:", writeError.index);
console.error("Error message:", writeError.errmsg);
});
} else {
console.error("Unexpected error:", error);
}
});

This approach helps identify and handle BulkWriteError effectively.

Unordered Inserts

Unordered inserts in MongoDB allow remaining documents to be inserted even if some insert operations fail.

• Continues inserting documents despite individual failures.
• Prevents the entire operation from stopping due to one error.
• Implemented using insertMany() with ordered: false.
• Useful for bulk insert operations.

**Query:

db.student.insertMany(
[
{_id:"stu203",name:"Sophia",age:28},
{_id:"stu206", name:"Emma", age:25}
],
{ordered: false}
)

**Output: