Sequelize Data Types

Introduction
In Sequelize, a popular Node.js ORM (Object-Relational Mapper) for working with relational databases like MySQL, PostgreSQL, SQLite, and others, data types are used to define the structure of the fields in a database table. These data types correspond to the types of data you can store in the database, such as strings, integers, dates, etc.
i) String Types -

STRING: A general-purpose variable-length string. By default, it creates a VARCHAR(255) column. You can specify the length if needed, e.g., Sequelize.STRING(100) for VARCHAR(100).

TEXT: Used for longer text strings. The length is not limited like STRING. Typically maps to TEXT or CLOB in databases.

CHAR: A fixed-length string, which will pad the value with spaces if the length is shorter than specified. E.g., Sequelize.CHAR(10).
ii) Numeric Types -

INTEGER: A standard integer type. You can specify options like UNSIGNED and ZEROFILL.

BIGINT: A larger integer type for storing big integers. Typically used for very large numbers that exceed the size of a standard INTEGER.

FLOAT: For floating-point numbers, which are decimal numbers that can have fractions.

DOUBLE: A double-precision floating-point number, offering more precision than FLOAT.

DECIMAL: A fixed-point number with a specified precision and scale, e.g., DECIMAL(10, 2).
iii) Boolean Type -

BOOLEAN: Used to store true or false values.
iv) Date and Time Types -

DATE: Stores date and time information. This maps to a DATETIME column in most databases.

DATEONLY: Stores only the date without the time. Typically maps to a DATE column.

TIME: Stores time information, e.g., 08:30:00.

NOW: A special type that represents the current date and time.
v) Binary Types -

BLOB: Used for storing binary data like images or files. Comes in different sizes, e.g., BLOB('tiny'), BLOB('medium'), etc.

UUID: A type for storing Universally Unique Identifiers (UUIDs). Useful for primary keys when you want to use UUIDs instead of auto-incrementing integers.
vi) JSON Types -

JSON: Stores JSON-formatted data. Supported natively by some databases like PostgreSQL.

JSONB: Similar to JSON, but stores data in a binary format, which allows for faster query performance in databases that support it.
vii) Enumerated Types -

ENUM: Allows you to define a list of possible values for a column. For example, Sequelize.ENUM('value1', 'value2', 'value3') restricts the column to only these values.
viii) Geometric Types -

GEOMETRY: Stores geometric data, such as points, lines, or polygons. Useful for spatial databases.

GEOGRAPHY: Similar to GEOMETRY but specifically for storing Earth-based coordinates.
ix) Other Types -

ARRAY: Allows you to store an array of items of a specific type. For example, Sequelize.ARRAY(Sequelize.STRING) will create an array of strings.

RANGE: Represents a range of values, such as [1, 10] or [DATE1, DATE2]. Useful in PostgreSQL for range types.

CIDR, INET, MACADDR: Used for storing network-related data like IP addresses.

Example

 const { Sequelize, DataTypes } = require('sequelize');
 const sequelize = new Sequelize('database', 'username', 'password', {
     host: 'localhost',
     dialect: 'mysql',
 });

 const User = sequelize.define('User', {
     id: {
         type: DataTypes.INTEGER,
         autoIncrement: true,
         primaryKey: true,
     },
     username: {
         type: DataTypes.STRING,
         allowNull: false,
     },
     email: {
         type: DataTypes.STRING,
         unique: true,
     },
     password: {
         type: DataTypes.STRING,
         allowNull: false,
     },
     birthdate: {
         type: DataTypes.DATEONLY,
     },
     isActive: {
         type: DataTypes.BOOLEAN,
         defaultValue: true,
     },
     preferences: {
         type: DataTypes.JSON,
     }
 });

 sequelize.sync();