How does FeatureBase differ to a traditional database?

The FeatureBase database uses a bitmap-based data format rather than pure bitmap indexes.

This high-level overview provides context by explaining:

data cardinality
data normalization in traditional databases

What is cardinality?

The relationships between data is called Cardinality and can be conceptualized as follows:

Example	Data relationships	Cardinality	Dimensions to represent
A country and capital city	one-to-one	High	Two
A country and citizens	one-to-many	Low	Three or more
Citizens and government services	many-to-many	Low	Three or more

High cardinality data

High cardinality data has a high number of unique relationships which can be represented in a two dimensional table:

StudentID	Student_name	Student_surname
01	Charles	Voss
02	Regina	Lambert
03	Peter	Joshua
04	Herman	Scobie

Low cardinality data

Data described as low cardinality have multiple relationships has a one-to-many or many-to-many relationship. For example:

StudentID	Subjects
01	English, French, History
02	French, Geography, Finance

Database normalization in relation to data cardinality

Database normalization has a set of normal forms which provide guidance on how data is represented.

The first normal form provides guidance on:

arranging data into two dimensions
the use of relation names, attributes and keys to reference rows

This means:

high and low cardinality data is saved to separate tables to remove duplication
the relationships (one-to-many and many-to-many) are maintained through the use of keys that reference specific rows in different tables.

For example, the low cardinality table above can be normalized as follows:

SubjectID	SubjectName
En	English
Fi	Finance
Fr	French
Ge	Geography
Hi	History

The SubjectID can then be linked with a key to the Students table StudentID key.

Benefits and costs of data normalization

Data normalization is not a perfect solution to data cardinality:

Benefit	Cost
Data integrity is easier to maintain	Data in separate tables makes indexing less efficient
Less duplication of data means faster inserts, updates and a smaller footprint	`JOIN` clauses are required to query data which makes queries more complex and therefore slower to return results

DBAs responsible for normalized systems use different methods to overcome the issues and should the benefits outweigh the costs, may denormalize data.

How does FeatureBase handle data cardinality?

FeatureBase does not use Database normalization. Instead, the system inserts data into a two-dimensional bitmap index which is:

designed to overcome issues with low cardinality data
optimized to reduce storage overheads and query execution time

Next step

Learn how data is encoded in bitmap indexes