33_MongoDB.pdf - CITS1402 Relational Database Management...

CITS1402
Relational Database Management Systems
Video 33 — MongoDB
Gordon Royle
Department of Mathematics & Statistics

NoSQL
The term NoSQL stands for
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Not SQL, or
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Not only SQL.
It is used to describe a range of database management sysetms
that do not use the relational model of data .
The most prominent NoSQL database is MongoDB which is a
document database.

The hype
NoSQL is often hyped as
“a modern , flexible and scalable solution for today’s mas-
sive and rapidly-changing cloud-based datasets”.
On the contrary, SQL is described as being
“A legacy system that is difficult to use , inflexible and does
not scale out well.”
NoSQL is portrayed as the “cool creative hipster” disrupt-
ing the fossilized stuffy world of SQL.

Structure
The main difference is whether to view data as highly structured or
loosely structured .
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In SQL, data is always structured into tables, and new data
must fit into the existing structure
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In MongoDB, data is largely unstructured , and new data of
any type can be added any where at any time

Data in RDBMS
In an RDBMS, tables create a strict template for data.
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Each table has a fixed schema , which determines the number,
type and name of all the columns
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The schema is designed in advance, and changing it is difficult
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Database is normalized to minimise redundancy and storage
requirements