MongoDB part-2

# Commands / Codes / Query :

1. Create Database

MongoDB creates a database when you first store data in it. You can switch to a database using the use command.

            use myDatabase

2. Drop Database

To drop a database, you can use the following command:

        use myDatabase
        db.dropDatabase()

3. Create Collection

You can create a collection by inserting a document into it. However, you can also use the createCollection method.

        db.createCollection("myCollection")

4. Drop Collection

To drop a collection, use:

        db.myCollection.drop()

5. Rename Collection

To rename a collection, use:

    db.myCollection.renameCollection("newCollectionName")

6. Insert Documents in the Collection

You can insert one or multiple documents:


// Insert one document
db.myCollection.insertOne({ name: "Alice", age: 30 })

// Insert multiple documents
db.myCollection.insertMany([
  { name: "Bob", age: 25 },
  { name: "Charlie", age: 35 }
])

7. Delete Documents

To delete documents, you can use deleteOne or deleteMany:

// Delete one document
db.myCollection.deleteOne({ name: "Alice" })

// Delete multiple documents
db.myCollection.deleteMany({ age: { $lt: 30 } })
 // Deletes all documents where age is less than 30

8. Update Document/Data

To update documents, you can use updateOne or updateMany:

// Update one document
db.myCollection.updateOne(
  { name: "Bob" },
  { $set: { age: 26 } }
)


// Update multiple documents
db.myCollection.updateMany(
  { age: { $gt: 30 } },
  { $set: { status: "senior" } }
)

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