Demoralization in NoSQL

Question

What is exactly demoralization in Nosql databases? I have read it means modelling different object types as different documents. My first guess was it means Aggregation without storing related data, i.e storing all rows of an entity in a single document with related data being referred by different documents for each row. But I'm not sure if this is correct or not? An example would be helpful. Thanks in advance

I do mean demoralization and not denormalization. I came across this term in the following links: 1. Couchbase documentation 2. Blog on Nosql

Answer 1

In the context of NoSQL (and database in general), demoralization is synonymous to denormalization. You can find mixed usage of demoralization and denormalization in many documents, or mention of demoralization being the opposite of normalization (so again, the same as denormalization) :

• What Is Meant By Denormalization In SQL?
• Database Denormalization
• What is demoralization?
• Normalization & Demoralization
• Designing databases - OLTP and OLAP

There is even that reference, which mention that some/many spell checkers suggest "demoralization" instead of "denormalization". This could explain why some people use demoralization : The effect of denormalization

Answer 2

NoSQL is a very, very wide field. It covers a lot of entirely different databases systems with entirely different concepts of how data should be structured.

The dogma of database normalization applies mostly to classic relational databases. The further a NoSQL database is away from the relational philosophy, the more do you have to question this dogma.

The philosophy of normalization assumes that database JOINs are cheap. So any data which can be split over multiple tables to remove redundancies should be split. But that doesn't apply to all NoSQL databases. Some of them don't support JOIN operations, so getting data stored in many different database entries can be a very expensive operation which either requires multiple consecutive queries to the database or expensive database-sided code execution. When you use one of those databases, you should store your data in a way that every performance-critical use-case can be fulfilled by looking up as few entries as possible, even when this means that you will have redundant data.

Those non-relational NoSQL databases which don't support JOINs frequently support arrays in database entries instead. These are usually the preferred way to model 1:n relations. So when 1 person has n telephone numbers, you wouldn't store the telephone numbers in a separate table/document/collection/whateveryoucallit, you would store them in an array in the person entry. There is usually no reason to handle telephone numbers as self-sustained entities when it wouldn't be for the inability of SQL to work properly with multiple values in a single field.

Answer 3

Denormalization in a NoSQL world would mean the same as in a RDBMS world. Duplication of data for read performance.