Definition

Database

A set of data that is accessible in various ways

Data in Data structure

The simpler way to imagine a database is the simpler form of data structure: the array

1. We must imagine a database as a structured data.
2. This data can be structured also if his data are not (unstructured).
3. The data can be represented as data structure (tree, graph, hash tables …).
4. A book is a database, with an index, is a searchable book

Database paradigm

Databases type

There are seven different database paradigm, so 7 way to organize informations into a computer.

• key-value
• Wide Column
• Document oriented
• Relational
• Graph
• Search
• Multi Model

Different usage

Database priorities

We can have different category of priorities:

• Data size (number of records)
• Write Many
• Read Many
• Number of computational element in data unit
• Speed
• Complex searches

The nature of data

The nature of your data will be the key for choosing the right database Paradigma

key value

Structure

The key value database is mainly a python dictionary

Usage

• In memory data (ram)
• Low number of computational element
• Speed
• low complex searches

Cache, Messaging,

Redis

The open source, in-memory data store used by millions of developers as a database, cache, streaming engine, and message broker.

https://redis.io/

wide Column

Structure

The wide Columns DB is and indexed collection of key-value records

Usage

• big Data size
• write many
• Low number of computational element
• low complex searches
• speed
• different column per record

handle large amounts of data and a high number of concurrent users. It is often used in applications that require high write throughput and low latency, such as online gaming, real-time analytics, and e-commerce.

RAP Tool

Rap Tool use the DDBlib that I wrote in 2006 in order to answer the logging procedure, the registration procedure. The class library implement the: GPD approach

• GET
• PUT will create if item not found.
• DELETE

Cassandra

https://cassandra.apache.org/_/index.html

Document Oriented

Structure

A key-value tree organised structure of json (or bson binary json) documents. Some still Use of XML for the document.

Usage

• big Data size
• write many
• Low number of computational element
• low complex searches
• speed
• different data per record

The particularity of those dbs is managing semi-structured data and developer friendly approach

CRUD

This is the one of feature of this 3 databases paradigm. The reason is their noSql approach, and the usage of CRUD managing of the record

• Create
• Retrive
• Update
• Delete

Other main feature is the missing declaration of the database structure.

MongoDB

https://www.mongodb.com/

Relational Model

Ted Codd

The relational model come from Edgar F "Ted". Codd The purpose of the relational model is to provide a declarative method for specifying data and queries: users directly state what information the database contains and what information they want from it

Structure

Usage

• big Data size
• write many/read many
• large number of computational element
• complex searches

You need to structure the data, describe relation, assign type to fields, declare index and search keys: is powerful but not an easy task to project and maintain

SQL

Structured Query Language,

SELECT user.name as member, groups.name as group
 FROM  user
 left JOIN  groups
   ON  groups.group_id = user.user_id

Maria DB

https://mariadb.com/

Graph

Structure a

Structure b

A graph database (GDB) uses graph structures for semantic queries with nodes, edges, and properties to represent and store data.

Usage

• big Data size
• write many/read many
• low number of computational element
• very complex searches
• speed

Is the database of choice when the relations among data are the most significative thing.

cypher

Cypher Query Language

neo4j

https://neo4j.com/

Full-text search

Structure

The full text search is an indexer that will catalogs words parsed from a list of document allowing a blaze fast search. (like index in books)

Usage

• big Data size
• read many
• very low number of computational element
• speed

Search engines, log browsers, data lake searches, filesystem browsers

elasticSearch

https://https://www.elastic.co/

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