Data Modeling

SQL vs NoSQL Database Differences

SQL	NoSQL
databases are primarily called as Relational Databases	database are primarily called as non-relational or distributed database
are table based databases	are document based, key-value pairs, graph databases or wide-column stores
have predefined schema	have dynamic schema
are vertically scalable	are horizontally scalable
are scaled by increasing he horse-power of the hardware	are scaled by increasing the databases servers in the pool ofresources to reduce load
databases uses SQL for defining and manipulating the data, which is very powerful	databases queries are focused on collection of documents
SQL databases are good fit for the complex query intensive environment	databases are not good fit for complex queries. On a high-level
SQL databases are vertically scalable. You can manage increasing load by increasing the CPU, RAM, SSD, etc, on a single server	NoSQL databases are horizontally scalable. You can just add few more servers easily in your NoSQL database infrastructure to handle the large traffic		——————————————-	————————————————-

SQL Database Examples :

1-MySQL Community Edition 2-MS-SQL Server Express Edition 3-Oracle Express Edition

NoSQL Database Examples :

1- MongoDB 2-CouchDB 3-Redis

Data Modeling – Table Elements

## Data Modeling – Table Relationships

Sequelize v6 :

Sequelize is a promise-based Node.js ORM tool for Postgres, MySQL, MariaDB, SQLite, Microsoft SQL Server, Amazon Redshift and Snowflake’s Data Cloud. It features solid transaction support, relations, eager and lazy loading, read replication and more.

example

const { Sequelize, Model, DataTypes } = require('sequelize');
const sequelize = new Sequelize('sqlite::memory:');

class User extends Model {}
User.init({
  username: DataTypes.STRING,
  birthday: DataTypes.DATE
}, { sequelize, modelName: 'user' });

(async () => {
  await sequelize.sync();
  const jane = await User.create({
    username: 'janedoe',
    birthday: new Date(1980, 6, 20)
  });
  console.log(jane.toJSON());
})();

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