Data Warehouse

Question 1

What is a Data Warehouse?

Answer 1

A relational datastore designed for analytic workloads, which is generally column-oriented data-store

Companies will have terabytes and millions of rows of data,
and they need a fast way to be able to produce analytics reports

Question 2

What do Data Warehouses typically do?

Answer 2

Data warehouses generally perform aggregation
• aggregation is grouping data eg. find a total or average
• Data warehouses are optimized around columns since
they need to quickly aggerate column data
Data warehouses are generally designed be HOT
• Hot means they can return queries very fast even though
they have vast amounts of data

Question 3

What is a Key Value Store?

Answer 3

A key-value database is a type of non-relational database (NoSQL) that uses a simple key-​value method to store data.

A key/value stores a unique
key alongside a value

Key values stores are dumb and fast.
They generally lack features like:
• Relationships
• Indexes
• Aggregation

Question 4

What is a document store?

Answer 4

A document store is a NOSQL database that stores documents as its primary data structure.

A document could be an XML but more commonly is JSON or JSON-Like

Document stores are sub-class of Key/Value stores