Mongo DB

MongoDB is an open source NoSQL database management program. NoSQL is used as an alternative to traditional relational databases. NoSQL databases are quite useful for working with large sets of distributed data. MongoDB is a tool that can manage document-oriented information, store or retrieve information.

Databases, collections, documents are important parts of MongoDB without them you are not able to store data on the MongoDB server. A Database contains a collection, and a collection contains documents and the documents contain data, they are related to each other.

MongoDB is an open source NoSQL database management program. NoSQL is used as an alternative to traditional relational databases. NoSQL databases are quite useful for working with large sets of distributed data. MongoDB is a tool that can manage document-oriented information, store or retrieve information.

It is a relational database. It is a non-relational and document-oriented database. Not suitable for hierarchical data storage. Suitable for hierarchical data storage. It is vertically scalable i.e increasing RAM. It is horizontally scalable i.e we can add more servers.

Using . find() as SQL LIKE Statement Search String Anywhere � To search all document where color name have �Pink� anywhere in string. ... Search String Start With � This will match all the string start with P characters. ... Search String End With � The dollar �$� symbol is used to match string ends with specific characters.

The limit () Method In MongoDB, the �limit ()� method is used to limit the records or documents present inside a collection. It accepts only one argument which is of number type. Depending on the value of the number, we can limit the number of documents to be displayed. This argument is an optional field inside the �limit ()� method, and when not specified then by default, it will display all the documents from the collection. The following is the basic syntax for �limit ()� method in MongoDB. >db.COLLECTION_NAME.find().limit(NUMBER)

You can write scripts for the mongo shell in JavaScript that manipulate data in MongoDB or perform administrative operation. This tutorial provides an introduction to writing JavaScript that uses the mongo shell to access MongoDB. Opening New Connections From the mongo shell or from a JavaScript file, you can instantiate database connections using the Mongo() constructor: new Mongo() new Mongo() new Mongo() Consider the following example that instantiates a new connection to the MongoDB instance running on localhost on the default port and sets the global db variable to myDatabase using the getDB() method:

MongoDB is a document-oriented NoSQL database used for high-volume data storage.

The installers for MongoDB are available in both the 32-bit and 64-bit format. The 32-bit installers are good for development and test environments. But for production environments you should use the 64-bit installers. Otherwise, you can be limited to the amount of data that can be stored within MongoDB.

In MongoDB, the first basic step is to have a database and collection in place.

The “insert” command can also be used to insert multiple documents into a collection at one time. The below code example can be used to insert multiple documents at a time.

In MongoDB, _id field as the primary key for the collection so that each document can be uniquely identified in the collection. The _id field contains a unique ObjectID value.

The method of fetching or getting data from a MongoDB database is carried out by using MongoDB queries. While performing a query operation, one can also use criterias or conditions which can be used to retrieve specific data from the database.

When the db.collection.find () function is used to search for documents in the collection, the result returns a pointer to the collection of documents returned which is called a cursor.

Mongo DB provides query modifiers such as the "limit" and "Orders" clause to provide more flexibility when executing queries. We will take a look at the following query modifiers

The concept of aggregation is to carry out a computation on the results which are returned in a query. For example, suppose you wanted to know what is the count of documents in a collection as per the query fired, then MongoDB provides the count() function.

MongoDB provides the update() command to update the documents of a collection. To update only the documents you want to update, you can add a criteria to the update statement so that only selected documents are updated.

One of the key concepts in MongoDB is the management of databases. Important aspects such as security, backup, access to databases are all important concepts when it comes to database administration.

Creating a user administrator in MongoDB is done by using the createUser method. The following example shows how this can be done.

Replication is referred to the process of ensuring that the same data is available on more than one Mongo DB Server. This is sometimes required for the purpose of increasing data availability.

Sharding is a concept in MongoDB, which splits large data sets into small data sets across multiple MongoDB instances.

Indexes are very important in any database, and with MongoDB its no different. With the use of Indexes, performing queries in MongoDB becomes more efficient.