MongoDB : Mangodb Delete

1. MongoDB Delete Operations

Definition

MongoDB provides various methods to delete documents from collections. The main delete operations are deleteOne() and deleteMany(). These operations allow you to remove documents that match specific criteria, helping you maintain and clean your database effectively.

Algorithm 1: Basic Document Deletion :-

Step 1: Connect to MongoDB database

Step 2: Select the target collection

Step 3: Define deletion criteria

Step 4: Choose delete method (deleteOne/deleteMany)

Step 5: Execute deletion operation

Example 1: Delete Single Document

// Delete a single user by username

db.users.deleteOne({

  username: "john_doe"

})

Algorithm 2: Multiple Document Deletion :-

Step 1: Identify deletion criteria

Step 2: Prepare query filter

Step 3: Use deleteMany() method

Step 4: Execute deletion

Step 5: Verify deleted count

Example 2: Delete Multiple Documents

// Delete all expired products

db.products.deleteMany({

  expiryDate: {

    $lt: new Date()

  }

})

Algorithm 3: Conditional Deletion :-

Step 1: Define complex conditions

Step 2: Combine multiple criteria

Step 3: Use logical operators

Step 4: Apply deletion operation

Step 5: Confirm results

Example 3: Conditional Delete with Multiple Criteria

// Delete inactive users with specific criteria

db.users.deleteMany({

  $and: [

    { lastLogin: { $lt: new Date(Date.now() - 30*24*60*60*1000) } },

    { status: "inactive" },

    { accountType: "trial" }

  ]

})