Preparing for MongoDB Certified Developer Associate Exam

I passed the MongoDB Certified Developer Associate in 25th April 2017. This is online exam and I would like to share my experienced how to prepare for this exam. About the Exam The MongoDB Certified Developer, Associate Level exam is intended for individuals with knowledge of the fundamentals of designing and building applications using MongoDB. We recommend this certification …

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MongoDB – Index and Performance

Indexing and Monitoring Indexes Explained Binary-tree indexes where a key references a document location. B-tree indexes are “n-array indexes” (you have multiple keys in a single child) { a: 1, b: -1} –> where 1 –> ASCending order and -1 –> DEScending order { a: 1 } –> the index will be ASC or DES …

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MongoDB – Replication

Replication Overview Replica Sets are equivalent to redundant copies across multiples virtual or physical machines with internal or attached storage space. The grace of the matter is to get a document on multiple servers getting multiples copies, redundant copies of the same data. Why would we do this? The primary reasons we do replication are: HA …

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[MongoDB] CRUD

CRUD Concepts Atomicity: write operation is atomic on the level of a single document, even if the operation modifies multiple embedded documents within a single document. $isolated Operator: This ensures that no client sees the changes until the write operation completes or errors out. $isolated does not work with sharded clusters: An isolated write operation does not …

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MongoDB – Philosophy and Features & Tools & Storage Engines

Philosophy and Features Availability: MongoDB maintains multiple copies of data called replicasets using native replication Security: Authentication.Authorization.Auditing.Encryption. Flexible Data Model:  MongoDB’s document data model makes it easy for you to store and combine data of any structure, without giving up sophisticated validation rules Multi-Datacenter Scalability: MongoDB can be scaled within and across geographically distributed data centers, providing …

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MongoDB – Sharding

Concepts Sharding: Sharding is a method for distributing data across multiple machines Sharded Cluster consists of the following components: shard, mongos, config servers Shard: Each shard contains a subset of the sharded data. Each shard can be deployed as a replica set. mongos: The mongos acts as a query router, providing an interface between client …

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MongoDB – Aggregation and Data Modeling

Data Modeling One to One Relations: Always embedded Considerations depending of access to data and how frequency access to a piece of the data (example of collections of employee and Resume (CV) ) Frequency access: to one document respect the other. If a document has a lot of information that do not need to update frequency …

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Master Detail pattern Transactions in MongoDB

In relational databases, transactions let you make reliable atomic updates to your data. Because relational schemas are often highly normalized, most logical transactions span multiple tables, so it is important to be able to do multiple updates atomically (all or nothing). While MongoDB does not have multi-document transactions, it makes up for this in many …

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