{"id":48431,"date":"2017-07-10T11:00:23","date_gmt":"2017-07-10T08:00:23","guid":{"rendered":"http:\/\/examples.javacodegeeks.com\/?p=48431"},"modified":"2023-08-03T10:44:24","modified_gmt":"2023-08-03T07:44:24","slug":"mongodb-collection-example","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/software-development\/mongodb\/mongodb-collection-example\/","title":{"rendered":"MongoDB Collection Example"},"content":{"rendered":"

Hello, in this tutorial we will see a study and understand the implementation of the collection in MongoDB. The idea is to understand how MongoDB works and deploy a highly scalable and performance-oriented database.<\/p>\n

1. Introduction<\/h2>\n

MongoDB is a document-oriented NoSQL database used for high volume data storage and provides high performance, high availability and automatic scaling.<\/p>\n

1.1 What is MongoDB?<\/h3>\n
    \n
  1. MongoDB is a document database<\/em> where each database contains collections<\/strong> which in turn contains documents<\/strong>. Each document can be different with varying number of fields. The size and content of each document can be different from each other and stored in a JSON-like format, Binary JSON (BSN)<\/a> in MongoDB<\/li>\n
  2. The rows (or the documents as called in MongoDB) doesn\u2019t need to have a schema defined beforehand. Instead, the fields can be created on the fly<\/li>\n
  3. Data model available within MongoDB allows developers to represent hierarchical relationships, store arrays, and other more complex structures more easily<\/li>\n
  4. MongoDB environments offers scalability<\/li>\n<\/ol>\n

    1.2 What is NoSQL?<\/h3>\n

    NoSQL Database is used to refer a non-SQL or non-relational database concepts.<\/p>\n

      \n
    1. Provides a mechanism for storage and retrieval of data other than tabular relations model used in relational databases<\/li>\n
    2. Provides more flexibility since all records are not restricted to the same column names and types defined across the entire table<\/li>\n
    3. Do not use SQL language to query data and provides no<\/strong> strict schema<\/li>\n
    4. With NoSQL, ACID (Atomicity, Consistency, Isolation, Durability) properties of database transactions are not guaranteed<\/li>\n
    5. Offers scalability and high performance for handling huge volumes of data<\/li>\n<\/ol>\n

      1.3 Why to use MongoDB?<\/h3>\n

      Below are some of the reasons why someone should start using MongoDB:<\/p>\n

        \n
      1. Document-oriented<\/strong>: Since MongoDB is a NoSQL type database, instead of having data in a relational type format, it stores the data in documents. Thus, making MongoDB very flexible<\/li>\n
      2. Ad hoc queries<\/strong>: MongoDB supports searching by field, range queries, and regular expressions searches. It often provides queries to return specific fields within documents<\/li>\n
      3. Indexing<\/strong>: Indexes can be created to improve the performance of searches within MongoDB<\/li>\n
      4. Automatic Load Balancing<\/strong>: MongoDB uses the concept of sharding to scale horizontally by splitting data across multiple MongoDB instances<\/li>\n
      5. Replication<\/strong>: MongoDB can provide high availability with replica sets<\/li>\n<\/ol>\n

        1.4 Advantages Over RDBMS<\/h3>\n

        Below are some of the key term differences between MongoDB and RDBMS:<\/p>\n\n\n\n\n\n\n\n\n
        RDBMS<\/strong><\/td>\nMongoDB<\/strong><\/td>\nDifference<\/strong><\/td>\n<\/tr>\n
        Table<\/td>\nCollection<\/td>\nIn RDBMS, the table contains the columns and rows which are used to store the data whereas, in MongoDB, this same structure is known as a collection. The collection contains documents which in turn contains Fields, which in turn are key-value pairs<\/td>\n<\/tr>\n
        Row<\/td>\nDocument<\/td>\nIn RDBMS, the row represents a single, implicitly structured data item in a table. In MongoDB, the data is stored in documents<\/td>\n<\/tr>\n
        Column<\/td>\nField<\/td>\nIn RDBMS, the column denotes a set of data values. These in MongoDB are known as Fields<\/td>\n<\/tr>\n
        Joins<\/td>\nEmbedded documents<\/td>\nIn RDBMS, data is sometimes spread across various tables and in order to show a complete view of all data, a join is sometimes formed across tables to get the data. In MongoDB, the data is normally stored in a single collection, but separated by using embedded documents. So there is no concept of joins in MongoDB<\/td>\n<\/tr>\n
        Primary Key<\/td>\n_id<\/td>\nIn MongoDB, the primary key is automatically set to the _id field<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        Apart from the terms differences, a few other differences are shown below:<\/p>\n

          \n
        1. Relational databases are known for enforcing data integrity. This is not an explicit requirement in MongoDB<\/li>\n
        2. RDBMS requires that data be normalized<\/a> first so that it can prevent orphan records and duplicates, thus resulting in more table joins and requiring more keys and indexes. This leads to performance issues which again is not an explicit requirement in MongoDB<\/li>\n<\/ol>\n

          1.5 Download and Install MongoDB<\/h3>\n

          You can watch this<\/a> video in order to download and install the MongoDB database on your Windows operating system.<\/p>\n

          Now, open up the MongoDB workbench and let\u2019s start building the collection in a NoSQL database!<\/p>\n

          2. MongoDB Collection Example<\/h2>\n

          As stated earlier, in MongoDB a database is used to store collections, and each collection is used to store documents. Lets dive in on how to create your first database and collection.

          <\/div> <\/div><\/p>\n

          2.1 Creating a MongoDB Database<\/h3>\n

          There is no CREATE DATABASE<\/code> statement in MongoDB like there is in SQL<\/a>. To create a database we need to use the use<\/code>\u00a0command\u00a0as shown below:<\/p>\n

          \"Fig.<\/a>
          Fig. 1: MongoDB Database Creation Command<\/figcaption><\/figure><\/p>\n

          Note:<\/strong> If the database already exists, a new one will not be created!<\/p>\n

          Upon successful execution, the following output is shown:<\/p>\n

          \"Fig.<\/a>
          Fig. 2: MongoDB Database Creation Output<\/figcaption><\/figure><\/p>\n

          Note<\/strong>: We get switched to the newly created database automatically.<\/p>\n

          2.2 Creating a MongoDB Collection<\/h3>\n

          A MongoDB collection<\/strong> is a grouping of MongoDB documents<\/em>. A collection is the equivalent of a table which is created in any other RDMS such as Oracle or MySQL. A collection exists within a single database and doesn’t enforce any sort of structure.<\/p>\n

          2.2.1 Two Ways to Create a Collection<\/h4>\n

          Here are two ways of creating collections:<\/p>\n