This article on DynamoDB vs MongoDB will help you compare these two databases so you can decide which one meets your needs better. Following pointers will be covered in this article,
- DynamoDB vs MongoDB
- Who uses DynamoDB and MongoDB?
- The Difference in Data Structures
- The Need for Indexes
- A Difference in Queries
- The Deployment of DynamoDB and MongoDB
- Replication and Clustering
DynamoDB vs MongoDB
MongoDB has been in the news for quite some time now. Since its introduction in the year 2009, a lot of companies around the world have started using this relational database management system, thanks to its wide array of features as well as great versatility. But even so, one often gets confused while choosing between the different options available in the market.
In today’s article we will compare MongoDB with DynamoDB and analyze which one will be better suited for your use and needs. Let’s begin!
Before we dive into the complexities of comparing both the platforms, let us first understand the individuality of both these platforms and what makes them stand out from one another.
DynamoDB
DynamoDB can be simply defined as a proprietary NoSql database management service that is provided by Amazon.com as a part of its AWS or Amazon Web Services program. While DynamoDB shares a lot of similarities with the original Dynamo program, it has a different underlying implementation that makes it unique. 
MongoDB
MongoDB can simply be defined as a cross platform relational database management system, which is offered as a standalone program. Classified under the NoSQL proprietary tag, MongoDB makes use of JSON like documents and Schema markups to handle database needs, thus making it unique.
Who uses DynamoDB and MongoDB?
Both DynamoDB and MongoDB have been around for some time now and thus companies worldwide use either of these programs to meet their database needs. Mentioned below are some of the most significant ones.
MongoDB
UPS, FaceBook, Google, BOSH, Adobe and Forbes, among many others.
DynamoDB
Samsung, Snapchat, New York Times, HTC, Dropcam and of course Amazon among many others.
Moving on with this article on DynamoDB vs MongoDB,
The Difference in Data Structures
Some of the key differences between MongoDB and DynamoDB lies in how they handle data structures. Mentioned below are some of the most significant ones.
DynamoDB
In DynamoDB, tables, attributes and items are the main components one has to work with. In simple terms, a table is a collection of items and each item is a collection of different attributes. The platform makes use of primary keys to identify each item present in a table and also secondary indexes to increase flexibility in queries.
MongoDB
On the other hand, MongoDB makes use of JSON like documents in order to store schema free data. One of the key differences between DynamoDB and MongoDB is the absence of the need to predefine data and structures, thus making way for the programmer to store different types of documents at once.
MongoDB in itself is a very powerful relational database management system. Since it is schema free, it allows the programmer to create documents for storing data, without the need of pre-defining it first.
An example of how data structures are different in MongoDB and DynamoDB can be found below.
Table | Column | Value | Records in DynamoDB while Collection | Key | Value | Document in MongoDB.
Moving on with this article on DynamoDB vs MongoDB,
The Need for Indexes
Indexes in a relational database management system gives one access to alternate query patterns, which come in handy when high speed queries are needed. In terms of indexing, there are quite a few differences between DynamoDB and MongoDB and they are listed as below.
DynamoDB
In DynamoDB, if you need to run a query you first need to create a secondary index. While creating the secondary index in DynamoDB, one needs to first specify its key attributes after which it can be used to run a query or scan a table by following standard procedure. One of the key things to note here is the fact that DynamoDB does not have a query optimizer and thus the creation of a secondary index is the only way to execute a query.
MongoDB
Indexes are a must in MongoDB. If in a certain situation, a document is missing an index, all the documents ever created needs to be scanned in order to match the query search. With that being said, the absence of an index can radically slow down the query process in MongoDB and thus it is needs to be created on a priority basis.
Moving on with this article on DynamoDB vs MongoDB,
A Difference in Queries
In order to understand the exact difference in queries between MongoDB and DynamoDB, take a look at the example below.
DynamoDB
db.query({
TableName: "customer"
})MongoDB db.customer.find()
The Deployment of DynamoDB and MongoDB
Another key area where DynamoDB and MongoDB differ, is how these relational database management systems were originally deployed.
DynamoDB: Most people believe that DynamoDB was written in Java, while some are of the opinion that DynamoDB was originally deployed in Node.Js. Whatever might be the case, DynamoDB supports the following languages: Java, Swift, JavaScript, Node.js, PHP, NET as well as Python.
MongoDB: MongoDB was coded entirely on C++ and it is available for download on Linux, Windows as well as Mac OS. Being coded on C++ MongoDB has support for a wide array of languages including but not limited to, Prolog, Python, Ruby, Java, JavaScript, PowerShell, ColdFusion and much more.
Moving on with this article on DynamoDB vs MongoDB,
Replication and Clustering
DynamoDB
Since DynamoDB is a part of the AWS or Amazon Web Services family, it actively makes use of Amazon DynamoDB Cross-Region Replication Library to sync across multiple regions in real time. When a programmer writes to one table in DynamoDB, the other tables present in other locations and or regions are updated in real time thanks to the fast operations from AWS.
MongoDB
On the other hand, single-master replication system which supports automatic election, and this feature comes built into the system. What this basically means that a programmer can setup a secondary database and program it to function as the primary one, if in a certain situation the primary becomes unavailable. In MongoDB, the first replica is referred to as the Primary and all others as Secondary ones.
Conclusion
Although at first glance it might seem that MongoDB and DynamoDB are quite similar, only upon further inspection will you realize that they serve very different functionalities. With that being said, depending upon your needs, make a choice between using either of them.
This bring us to the end of this article on MongoDB vs DynamoDB.
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