Cara menggunakan mongodb flat vs nested
In today’s world exponentially growing unstructured data is the new normal thing for business. Managing and getting insights from unstructured data is challenging for a growing organization. According to research, the volume of unstructured data is larger than the volume of structured data at play. Traditional data handling methods such as Relational Database Management Systems (RDBMS) aren’t recommended while handling semi-structured or unstructured data. This is where Document-oriented, Open-source NoSQL Databases, such as MongoDB come to the rescue. Show
Querying is a basic database management system operation that can modify, retrieve, insert, and delete data. This article aims to discuss a step-by-step guide on how to perform a Nested Query in MongoDB and some of the important aspects of nested queries as well. Table of ContentsWhat is MongoDB?Image SourceMongoDB is an open-source document-oriented NoSQL database. It is developed and maintained by MongoDB.Inc under the Server Side Public License (SSPL) and was first released in February 2009. MongoDB was designed to handle large volumes of data efficiently. It also supports data storage and retrieval in the document or key-value format. It is available as Cloud as well as on-primes i.e Server services. MongoDB offers both an Enterprise and Community version of its powerful distributed document database. MongoDB’s document model is quite famous in the developer community as it provides all the capabilities needed to meet the most complex requirements at any scale. It provides drivers for 10+ languages including C++, Java, Ruby,Node.js, Perl, C#, Scala, and other programming languages as well. Key Features of MongoDBImage SourceThe key features of MongoDB are as follows:
What is Nested Query?Nested queries or Embedded queries are those queries that have another query embedded in them. For nested queries, the internal query is executed only once at the beginning. The outer query is executed using the results of the inner query. Therefore, the internal query is used when executing the external query. Replicate Data From MongoDB in Minutes Using Hevo’s No-Code Data PipelineHevo Data, a Fully-managed Data Pipeline platform, can help you automate, simplify & enrich your data replication process in a few clicks. With Hevo’s wide variety of connectors and blazing-fast Data Pipelines, you can extract & load data from 100+ Data Sources such as MongoDB straight into your Data Warehouse or any Databases. To further streamline and prepare your data for analysis, you can process and enrich raw granular data using Hevo’s robust & built-in Transformation Layer without writing a single line of code! GET STARTED WITH HEVO FOR FREE Hevo is the fastest, easiest, and most reliable data replication platform that will save your engineering bandwidth and time multifold. Try our 14-day full access free trial today to experience an entirely automated hassle-free Data Replication! What is MongoDB Nested Query?MongoDB delivers an upstanding feature named Embedded or Nested Document. An Embedded or Nested Document is a type of document that contains one document within another. That is if a collection contains one document, that document contains another document, another document contains another child document, and so on, such document types are called embedded/nested documents. A few points to note here:
Understanding MongoDB Nested Query AspectsMongoDB database doesn’t support sub queries or joins. Embedded or Nested Query feature is available in MongoDB to get joins or sub queries functionality. Creating an Embedded/Nested DocumentMongoDB makes it easy to embed a document in another document. As you know, the mongo shell documentation is defined by curly braces ({}), and inside these curly braces are field/value pairs. You can use curly braces {} to embed or set another document within these fields. This document can include field-value pairs or other partial documents. Syntax:
Example of Nested Query in MongoDB: There is a “company” database as shown in the following image. This database now has a collection named “Inventory” that contains the following documents: The following nested query will insert into the inventory collection:
You can notice in the inventory collection you have 5 documents that contain the nested document. You can retrieve these nested documents by using db.collection.find() method in mongosh. This document has a field name “item” that contains another document, and this document contains two fields with values (that is, sku, color). What Makes Hevo’s ETL Process Best-In-Class?Providing a high-quality ETL solution can be a difficult task if you have a large volume of data. Hevo’s automated, No-code platform empowers you with everything you need to have for a smooth data replication experience. Check out what makes Hevo amazing:
MongoDB Nested Query Match TypesYou can use the query filter document { The equality condition will look for embedded documents that need an exact match with the specified document, including the order of the fields. For example, the following query selects all documents where the field size equals the document { h: 14, w: 21, uom: “cm” }: Query:
MongoDB Nested Query Match on a Nested FieldYou can use the dot notation (“field.nestedField”) to specify query criteria for fields in embedded/nested documents. For queries that use dot notation, fields and nested fields must be enclosed in double-quotes. This is what the syntax would look like:
For example:
The above example selects all documents whose size field nested field uom is equal to “in”. MongoDB Nested Query Match Using Query OperatorIn query filter documents, you can use query operators to specify conditions of the form of the following syntax: Syntax:
MongoDB provides $lt to select documents whose field values are less than the defined values. This applies to documents that do not contain fields. Syntax:
Example: db.inventory.find( { “size.h”: { $lt: 15 } } ) The above query will return all the documents where “size.h”less than 15.
Similar to the above discussed less-than operator, you can use the greater than the operator in a MongoDB nested query. $gt operator is used to select documents whose field values are greater than the defined values. Syntax:
Example: db.inventory.find( { “size.h”: { $gt: 55 } } ) The above query will return all the documents where “size.h” greater than 55.
MongoDB provides $ne to select documents whose field values are not equal to the defined values. This applies to documents that do not contain fields. Syntax:
Example: db.inventory.find({ “item.color”: { $ne: “blue”} }) The above query will return all the documents where item color is not blue. MongoDB Nested Query Match Using Query Operator AND ConditionYou can use the following query to select all documents whose nested field h is less than 15, the nested field uom equals “in”, and the status field equals “D”: Example: ConclusionIn this article, we discussed MongoDB Nested Query and various methods to perform the Nested query in MongoDB. And, we have covered the different operations with examples. Visit our Website to Explore HevoMongoDB is a great tool for storing your business data. However, at times, you need to transfer this data to a Data Warehouse for further analysis. Building an in-house solution for this process could be an expensive and time-consuming task. Hevo Data, on the other hand, offers a No-code Data Pipeline that can automate your data transfer process, hence allowing you to focus on other aspects of your business like Analytics, Customer Management, etc. This platform allows you to transfer data from 100+ sources like MongoDB to Cloud-based Data Warehouses like Snowflake, Google BigQuery, Amazon Redshift, etc. It will provide you with a hassle-free experience and make your work life much easier. |