PostgreSQL - Data Types

In this tutorial we will learn about of the commonly used data types in PostgreSQL.

About Data Types

Data types tells us about the type of data that is stored in a column.

Following are some of the commonly used data types in PostgreSQL.

• Numeric Type
• Boolean Type
• UUID Type
• XML Type
• JSON Type
• Monetary Type
• Character Type
• Binary Type
• Date/Time Type

Numeric Type

Numeric types helps us to store numbers. The following table lists the different numeric types.

• Integer
• Numeric and Decimal
• Floating point
• Serial

Integer

These data types are used to store integer values like -2, 0, 10 etc.

Data Type	Size (byte)	Min value	Max value
smallint	2	-32768	+32767
integer	4	-2147483648	+2147483647
bigint	8	-9223372036854775808	+9223372036854775807

Numeric and Decimal

Numeric and Decimal are of variable size as the precision is user specified.

Data Type	Size (byte)	Range
numeric	variable	up to 131072 digits before the decimal point; up to 16383 digits after the decimal point
decimal	variable	up to 131072 digits before the decimal point; up to 16383 digits after the decimal point

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PostgreSQL - Getting Started

This is an introduction to PostgreSQL database.

What is PostgreSQL?

PostgreSQL is a RDBMS or Relational Database Management System. It is one of the popular and most advanced open source relational database and was developed at Berkeley Computer Science Department (University of California).

Versions of PostgreSQL

PostgreSQL can be installed on Windows, Mac and Linux personal computers and can also be installed on servers like Google Cloud, AWS (Amazon Web Services) etc.

Connecting to the database using psql

After installing the PostgreSQL database on your computer you can connect to it using psql command from your terminal.

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How to install Postgres.app to use PostgreSQL database on Mac

In this tutorial we will learn to install Postgres.app to use PostgreSQL database on Mac.

What is Postgres.app?

Postgres.app is a full-featured PostgreSQL installation packaged as a standard Mac app. -- https://postgresapp.com

Download

Visit postgresapp.com and download the software on your Mac.

Run the installer and move the Postgres.app into the Applications directory.

Default settings

Postgres.app will install on your Mac with the following default settings.

Host	localhost
Port	5432
User	your system user name
Database	same as user
Password	none
Connection URL	postgresql://localhost

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ES6 - Template Literals (Template strings)

Watch the video tutorial: ES6 Template Literals (Template strings) #02

In this ES6 JavaScript tutorial we will learn about Template Literals (Template strings).

What are Template Literals?

Template literals are string literals that allows us to embed expressions, multi-line strings and string interpolation.

Template literals are enclosed using backtick ` ` instead of single quotes and double quotes.

Let's print the string Hello World using single and double quotes.

console.log('Hello World');
console.log("Hello World");

Now, let's print the same string using template literal.

console.log(`Hello World`);

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ES6 - var let const

Check out the tutorial video: ES6 var let const #01

In this ES6 JavaScript tutorial we will learn to create variables using var, let and const.

The var keyword

Alright, let's begin by creating a variable using the var keyword.

Let's say we want to create a variable x and assign it a value 10. So, we will write the following line.

var x = 10;

Now, if we want to print the value of x we can console log it by writing the following line.

var x = 10;
console.log(x);

And we get the output 10.

Few important points we must note while using the var keyword to declare variables.

We can redefine the same variable x again and we will not get any error.

So, we can write something like the following.

var x = 10;
console.log(x); // 10
var x = 20;
console.log(x); // 20

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