MongoDB : Mangodb Update

1. MongoDB Update Operations

Definition

MongoDB update operations modify existing documents in a collection. The update operations provide various methods to update document fields, including setting new values, incrementing values, updating arrays, and performing complex updates using operators.

Algorithm 1: Basic Document Update :-

Step 1: Select the collection

Step 2: Specify update criteria

Step 3: Choose update operator

Step 4: Define update values

Step 5: Execute update operation

Example 1: Basic Field Update

// Update student grade

db.students.updateOne(

  { name: "John Doe" },

  {

    $set: {

      grade: "A",

      lastUpdated: new Date()

    }

  }

)

Algorithm 2: Array Update Operations :-

Step 1: Identify array field

Step 2: Choose array update operator

Step 3: Specify array elements

Step 4: Define update conditions

Step 5: Execute array update

Example 2: Array Update

// Update array elements

db.users.updateOne(

  { _id: ObjectId("123") },

  {

    $push: {

      hobbies: "reading"

    },

    $pull: {

      oldHobbies: "gaming"

    }

  }

)

Algorithm 3: Multiple Document Update :-

Step 1: Define update criteria

Step 2: Prepare update operations

Step 3: Set update options

Step 4: Apply bulk updates

Step 5: Verify results

Example 3: Multiple Document Update

// Update multiple documents

db.products.updateMany(

  { category: "electronics" },

  {

    $inc: { price: 10 },

    $set: {

      updated: true,

      lastModified: new Date()

    }

  }

)