sql.txt

SQL : 
Data -->
DataBase -->
RDBMS --->
DT----------------------------
		integer-	BigINT,smallInt,int , tiny int -->127 to -128
		String - 	Character -->size[255]
		integer+String->	Address-->VarChar size[255]
		integer+String->	text -->n number of lines 
		folating------->	float,double,decimal
		boolean-------->	true , false
		
		Date ----------->  date,datetime,time,timestamp
---------------------------------
Opeartions
		Airthmatic 
		comparative /relatives ope
		logical--And -(both) OR--(one) NOT ()
		AND -----both side will be true--0
		OR ------One side will be true --1
		
SCHEMAS ---it is collection of DATABASE 
	Database --
	logical structure   ---tables ,database
	phyical structure   ---size , memory 
	
	
	keywords
	
	fasle---0
	true---1
	
	declarative ---how to do not saying what to do 
	
	Types of commands 
		create ---database ,tables
		database
		syntax : - create database databaseName;
tables	
		create table tablename(
		//query
		
		);
		
		
		example: create database customer;
		
		create table customer_Details(
		customer_ID int ,//int size defaultt 11
		customer_name varchar(15)//name should be less than 15 character
		customer_number bigint,
		customer_Address varchar(200)
	);
	select * from customer_details;//tables view 
	desc customer_details;//table description
	show columns from customer_order;//columns
	constraint //not null 
				keywords/rule to write 
	unique----id should be 
	
	check ----restrict the timings 
			condition, check age >18	
	
	primary key-- combination of is not null and unique
	
	foreign key --parent to child (any properties u can make it as primary key)
	
	alter--->it is change the structure of the table 
	
	modify---
	alter table customer_transaction modify transaction_status boolean  default false;
	
	add----
	alter table customer_transaction add transaction_Addresee varchAR(20)  not null;
	
	drop-----
	alter table customer_transaction drop transaction_Addreses;
	desc---
	desc customer_transaction;
	
11/04/2021
Administartive commonds
		show databases  it wil show the all database name 
		show tables
DDL -- data defination language -----create ,alter,drop,
DML -- data manipulation language ---insert, 

reaname table 
		alter table product rename to product_Details;
rename column name 		
		alter table product_details rename column product_price to productPRice;
truncate