Session Commands - ( Database and Collection Commands )

A session in MongoDB allows users to start a transaction, perform multiple operations and commit or abort the transaction. In this page, we will discuss the commonly used session commands for databases and collections in MongoDB.

Syntax

The syntax for session commands in MongoDB follows a basic pattern. Here is the general syntax:

session.<command>()

Example

Here's an example that demonstrates the use of session commands in MongoDB:

// Start a client session
const session = client.startSession();

// Use the session to start a transaction, perform some operations, and then commit or abort the transaction
session.startTransaction();
try {
  // Perform multiple operations within the transaction
  const db = session.getDatabase('myDatabase');
  const collection = db.getCollection('myCollection');
  collection.insertOne({ name: 'John Doe', age: 30 });

  // If all operations were successful, commit the transaction
  session.commitTransaction();
} catch (error) {
  // If any operation fails, rollback the transaction
  session.abortTransaction();
  console.log('Transaction aborted:', error);
}

Output

The output of session commands varies depending on the command used. The operations specified within a transaction either commit or roll back based on the success rate of the operations.

Explanation

MongoDB provides several commands for performing database and collection operations within a transaction. Some of the commonly used session commands are:

• startTransaction(): Starts a transaction on a client session.
• commitTransaction(): Commits a transaction on a client session.
• abortTransaction(): Aborts or rolls back a transaction on a client session.
• withTransaction(): Performs specified operations within a transaction.

Use

Session commands are used when a user wants to perform multiple operations as part of a single transaction. This is useful when the user wants to ensure data consistency within the database, meaning that all the related data must either be committed or rolled back as a single unit. Session commands can be used when performing operations such as transactions, committing data to a replica set or a sharded cluster in MongoDB.

Important Points

• Session commands allow users to perform multiple operations within a single transaction.
• Transactions protect data consistency by ensuring that related data must be either committed or rolled back as a single unit.
• Session commands are used when performing operations such as transactions, committing data to a replica set, or a sharded cluster in MongoDB.

Summary

In this page, we learned about session commands in MongoDB used when performing database and collection operations within a single transaction. We covered the syntax, example, output, explanation, use, and important points of session commands. Session commands are essential when it comes to preserving the data consistency within the database.