Mongo db Shell Commands

 MongoDB shell commands allow you to interact with a MongoDB database from the command-line interface using the mongosh shell. Below is a categorized list of commonly used commands:

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Basic MongoDB Shell Commands

1. Start the MongoDB Shell
   
   mongosh
2. Show Available Databases
   
   show dbs
   
   
3. Switch to a Database
   
   use databaseName
4. Show Current Database
   
   db

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Collection Commands

1. Show Collections in the Current Database
   
   show collections
2. Create a Collection
   
   db.createCollection("collectionName")
3. Drop a Collection
   
   db.collectionName.drop()

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Insert Data

1. Insert a Single Document
   db.collectionName.insertOne({ key1: "value1", key2: "value2" })
   
   
2. Insert Multiple Documents
   
   db.collectionName.insertMany([

       { key1: "value1", key2: "value2" },

       { key1: "value3", key2: "value4" }

       ])

   
   

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Query Data

1. Find All Documents
   db.collectionName.find()
   
   
2. Find with a Filter
   db.collectionName.find({ key1: "value1" })
   
   
3. Find One Document
   
   db.collectionName.findOne({ key1: "value1" })
4. Limit Results

   db.collectionName.find().limit(5)
5. Sort Results
   db.collectionName.find().sort({ key1: 1 }) // 1 for ascending, -1 for descending
   
   

Update Data

1. Update a Single Document

   db.collectionName.updateOne(
       { key1: "value1" },  // Filter
       { $set: { key2: "newValue" } }  // Update
   )
   

2. Update Multiple Documents

   db.collectionName.updateMany(
       { key1: "value1" }, 
       { $set: { key2: "newValue" } }
   )
   

3. Replace a Document

   db.collectionName.replaceOne(
       { key1: "value1" }, 
       { key1: "newKey", key2: "newValue" }
   )
   

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Delete Data

1. Delete a Single Document

   db.collectionName.deleteOne({ key1: "value1" })
   

2. Delete Multiple Documents

   db.collectionName.deleteMany({ key1: "value1" })
   

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Indexing

1. Create an Index

   db.collectionName.createIndex({ key1: 1 })  // 1 for ascending, -1 for descending
   

2. View All Indexes

   db.collectionName.getIndexes()
   

3. Drop an Index

   
   db.collectionName.dropIndex("indexName")
   

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Aggregation

1. Simple Aggregation Pipeline

   db.collectionName.aggregate([
       { $match: { key1: "value1" } },
       { $group: { _id: "$key2", total: { $sum: "$key3" } } }
   ])
   

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Administrative Commands

1. Check Server Status

   db.serverStatus()
   

2. View Current Operations

   db.currentOp()
   

3. Kill an Operation

   db.killOp(opId)
   

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These commands cover basic CRUD operations, indexing, and administrative tasks. Let me know if you want to dive deeper into any specific area!