Understanding MongoDB Database.
                     UNDERSTANDING MONGODB 
DATABASE
WHAT IS 
MONGODB?
• MongoDB is a document-oriented 
NoSQL database used for high 
volume data storage. 
• Instead of using tables and rows as 
in the traditional relational 
databases, MongoDB makes use of 
collections and documents.
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MONGODB 
FEATURES
• Each database contains collections 
which in turn contains documents. 
The size and content of each 
document can be different from 
each other.
• The document structure is more in 
line with how developers construct 
their classes and objects in their 
respective programming languages. 
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MONGODB 
FEATURES 
CONT.
• The rows doesn't need to have a 
schema defined beforehand. 
Instead, the fields can be created on 
the fly.
• The data model available within 
MongoDB allows you to represent 
hierarchical relationships, to store 
arrays, and other more complex 
structures more easily.
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KEY COMPONENTS 
OF MONGODB 
ARCHITECTURE
• _id – The _id field represents a 
unique value in the MongoDB 
document. The _id field is like the 
document's primary key.
• Collection – This is a grouping of 
MongoDB documents. 
• Cursor – This is a pointer to the 
result set of a query. Clients can 
iterate through a cursor to retrieve 
results.
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KEY COMPONENTS OF 
MONGODB 
ARCHITECTURE CONT.
• Database – This is a container for 
collections like in RDMS wherein it is 
a container for tables. 
• Document - A record in a MongoDB 
collection is basically called a 
document. The document, in turn, 
will consist of field name and values.
• Field - A name-value pair in a 
document. A document has zero or 
more fields. Fields are analogous to 
columns in relational databases.
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WHY USE 
MONGODB?
• Document-oriented – Since 
MongoDB is a NoSQL type database, 
instead of having data in a relational 
type format, it stores the data in 
documents. 
• Ad hoc queries - MongoDB supports 
searching by field, range queries, 
and regular expression searches.
• Indexing - Indexes can be created to 
improve the performance of 
searches within MongoDB. 
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WHY USE 
MONGODB CONT.
• Replication - MongoDB can provide 
high availability with replica sets. A 
replica set consists of two or more 
mongo DB instances. 
• Load balancing - MongoDB uses the 
concept of shading to scale 
horizontally by splitting data across 
multiple MongoDB instances.
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DATA MODELLING 
IN MONGODB
• MongoDB's collections do not 
enforce document structure. 
• This sort of flexibility is what makes 
MongoDB so powerful.
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 NEEDS OF THE 
APPLICATION 
• Look at the business needs of the 
application and see what data and 
the type of data needed for the 
application. 
• Based on this, ensure that the 
structure of the document is 
decided accordingly.
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DATA RETRIEVAL 
PATTERNS
• If you foresee a heavy query usage 
then consider the use of indexes in 
your data model to improve the 
efficiency of queries.
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