Here we discuss about ten most commonly used commands for MongoDB beginners. Please feel free to comment and make suggestions if I failed to mention any important points!
After installation:
1. Start MongoDB: Open cmd and run mongod
>mongod
Open another cmd and run this commend
>mongo
2. Show All Databases:
>show dbs
3. Select Database to Work With:
>use databaseName
4. Authenticate and Log Out From Database:
// Authenticate
//
>db.auth("username", "password");
//
// Logout
//
>db.logout()
6. Create a Collection:
>db.createCollection("collectionName");
7. Insert a Document in a Collection:
Once a collection is created, the next step is to insert one or more documents. Following is a sample command for inserting a document in a collection.
// Insert single document
//
>db.<collectionName>.insert({field1: "value", field2: "value"})
//
// Insert multiple documents
//
>db.<collectionName>.insert([{field1: "value1"}, {field1: "value2"}])
>db.<collectionName>.insertMany([{field1: "value1"}, {field1: "value2"}])
8. Save or Update Document:
The save command can be used to either update an existing document or insert a new one depending on the document parameter passed to it.
// Matching document will be updated; In case, no document matching the ID is found, a new document is created
//
>db.<collectionName>.save({"_id": new ObjectId("jhgsdjhgdsf"), field1: "value", field2: "value"});
9. Display Collection Records:
The following commands can be used to retrieve collection records:
// Retrieve all records
>db.<collectionName>.find();
// Retrieve limited number of records; Following command will print 10 results;
>db.<collectionName>.find().limit(10);
// Retrieve records by id
>db.<collectionName>.find({"_id": ObjectId("someid")});
// Retrieve values of specific collection attributes by passing an object having
// attribute names assigned to 1 or 0 based on whether that attribute value needs
// to be included in the output or not, respectively.
>db.<collectionName>.find({"_id": ObjectId("someid")}, {field1: 1, field2: 1});
>db.<collectionName>.find({"_id": ObjectId("someid")}, {field1: 0}); // Exclude field1
//
// Collection count
//
>db.<collectionName>.count();
10. Administrative Commands:
Following are some of the administrative commands that can be helpful in finding collection details such as storage size, total size, and overall statistics.
// Get the collection statistics
//
>db.<collectionName>.stats()
>db.printCollectionStats()
//
// Latency statistics for read, writes operations including average time taken for reads, writes
// and related umber of operations performed
//
>db.<collectionName>.latencyStats()
//
// Get collection size for data and indexes
//
>db.<collectionName>.dataSize() // Size of the collection
>db.<collectionName>.storageSize() // Total size of document stored in the collection
>db.<collectionName>.totalSize() // Total size in bytes for both collection data and indexes
>db.<collectionName>.totalIndexSize()// Total size of all indexes in the collection
For more details contact at here