Keywords in Python

Keywords are special reserved words which have predefined meaning. Each keyword have a special meaning and a specific operation. Give below keywords are used in python;

True	False	and
asset	def	None
as	class	from
continue	break	finally
global	elif	del
for	if	else
except	import	raise
pass	return	or
nonlocal	try	in
lambda	is	not

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Introduction of SQL

Introduction of SQL SQL (Structure Query Language) was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce in the early 1970s. This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasi-relational database management system. Features of SQL SQL is not a case sensitive language. Every commands in SQL should ends with semicolon(;). SQL can also called as sequel (SEQUEL). SQL Sub Language SQL is mainly divided into four sub language Data Definition Language(DDL) Data Manipulation Language(DML) Transaction Control Language(TCL) Data Control Language(DCL) Only for remember You can remember all these command like below; DDL Commands "dr. cat" d-Drop, r-Rename, c-Create, a-Alter, t-Truncate. DML commands "sudi". s-Select, u-Update, d-Delete, i-Insert.

SQL Syntax

SQL Syntax SQL follows some unique set of rules and guidelines called Syntax . Some basic guidelines related to SQL Syntax are given below; SQL is not case sensitive. Commonly SQL keywords are written in uppercase. You can write SQL statements in one line or in multiple lines. SQL are depends on relational algebra and tuple are relational calculus. SQL statement SQL statements are started with any of the SQL commands/keywords like SELECT, INSERT, UPDATE, DELETE, ALTER, DROP etc. and the statement ends with a semicolon (;). Syntax SELECT * FROM table_name; Why use semicolon after SQL statements ? Semicolon is used to separate SQL statements. It is a standard way to separate SQL statements in a database system in which more than one SQL statements are used in the same call. Some Basic Commands SELECT: It is used for Retrive data from a database. UPDATE: It is used for updates data in database. DELETE: It is used for deletes data from da...

SQL Default Constraints

SQL Default Constraints Default Constraints is used to insert a default value into a column. The default value will be added to all new records, if no other value is specified. My SQL or SQL Server or Oracle or MS Access create table Employee ( e_id number(3) NOT NULL,, e_name varchar(15), sal number(5), City varchar(255) DEFAULT 'Delhi', ); In above syntax in city column by default value for city of every employee is delhi. SQL DEFAULT Constraint on Alter Table My SQL ALTER TABLE Employee ALTER City SET DEFAULT 'delhi' SQL Server or MS Access ALTER TABLE Employee ALTER COLUMN City SET DEFAULT 'delhi' Oracle ALTER TABLE Employee ALTER City SET DEFAULT 'delhi' Drop Default Constraints My SQL ALTER TABLE Employee ALTER City DROP DEFAULT SQL Server or Oracle or MS Access ALTER TABLE Employee ALTER COLUMN City DROP DEFAULT

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