Chapter 1 introduction to sql server

Introduction To DBMS and
SQL SERVER
DDL,DML,DCL

What is Database?
• A collection of information organized in such a way that
a computer program can quickly select desired pieces of data.
• You can think of a database as an electronic filing system

Where do we use Database?
Front End: done in PHP / .Net / JSP or
any server side scripting languages
Stores data at the Back end
database in MYSQL/SQL Server /
Oracle or any other DBMS

Database management system (DBMS)
“Simply DBMS helps you to create and manage databases-
same like MSWord helps you to create or manage word
documents.”

Database management system (DBMS)
– DBMS is a computer software providing the interface
between users and a database (or databases)
– It is a software system designed to allow the definition,
creation, querying, update, and administration of
databases
– Different types of DBMS are RDBMS, Object Oriented
DBMS, Network DBMS, Hierarchical DBMS
– Examples :Oracle, Mysql, PostgreSQl, SQL server, Firebird
etc

“ The RDBMS follows
Entity- Relationship model”

What is Entity – Relationship (ER) Data
Model ?
In ER model all the data will be viewed as Entities, Attributes and
different relations that can be defined between entities
• Entities
– Is an object in the real world that is distinguishable from
other objects
– Ex. Employees, Places
Attributes
– An entity is described in the database using a set of
attributes
– Ex. Employee_Name, Employee_Age, Gender

Entity – Relationship (ER) Data Model ?
Relationships
– A relationship is an association among two or more entities
• So a relation means simply a two dimensional table
• Entities will be data within a table
• And attributes will be the columns of that table

Relational model basics
• Data is viewed as existing in two dimensional tables known as
relations.
• A relation (table) consists of unique attributes (columns) and
tuples (rows)
Emp_id Emp_name Emp_age Emp_email
1000 Deepak 24 dk@gmail.com
1001 Aneesh 23 an@gmail.com
1002 Naveen 25 nn@gmail.com
1003 Jacob 25 jb@gmail.com
Attributes/Fields/Columns
Rows/
Records/
Tuples

Relational model Example
Pk_int_id Vchr_Designation
1 Area manager
2 Supervisor
3 Software Engineer
4 Clerk
Pk_int_id Vchr_place
1 Mumbai
2 Kolkata
3 Bangalore
4 Cochin
Tbl_placeTbl_designation
Emp_id Emp_name Emp_age Emp_email Fk_int_designation fk_int_place_id
1000 Deepak 24 dk@gmail.com 1 1
1001 Aneesh 23 an@gmail.com 2 1
1002 Naveen 25 nn@gmail.com 1 2
1003 Jacob 25 jb@gmail.com 3 4
Tbl_employee

Keys in relational Model
• Primary Key
• Here there are 2 employees with name “Deepak” but each
can be identified distinctly by defining a primary key

Keys in relational Model
• Primary Key
• The PRIMARY KEY constraint uniquely identifies each record in
a database table.

Relational model Example
Pk_int_id Vchr_Designation
1 Area manager
2 Supervisor
3 Software Engineer
4 Clerk
1 Mumbai
2 Kolkata
3 Bangalore
4 Cochin
Tbl_placeTbl_designation
Emp_id Emp_name Emp_age Emp_email Fk_int_designatio
n
fk_int_place_id
1000 Deepak 24 dk@gmail.com 1 1
1001 Aneesh 23 an@gmail.com 2 1
1002 Naveen 25 nn@gmail.com 1 2
1003 Jacob 25 jb@gmail.com 3 4
Tbl_employee
Foreign Key
A Foreign key in one table points to a Primary Key of another table.

SQL SERVER
• Microsoft SQL (Structured Query Language) Server is a
relational database management system developed by
Microsoft.
• As a database server, it is a software product whose primary
function is to store and retrieve data as requested by other
software applications, be it those on the same computer or
those running on another computer across a network
(including the Internet). The SQL phrase stands for Structured
Query Language
• In January 2008, Sun Microsystems bought MySQL for $1
billion

SQL SEVER
• Data Definition Language (DDL)
• are used to define the database structure or schema.
– Create
– Alter
• Data Manipulation Language (DML)
• are used for managing data within schema objects.
– Insert
– Update
• Data Control Language (DCL) statements.
• Used to create roles, permissions, and referential integrity as well it is used to
control access to database by securing it.
– Grant
– Revoke
– Drop
– Truncate
– Delete
– SELECT
– Commit
– Rollback

Create - Database
• To create a Database
– Syntax : CREATE DATABASE dbname;
– Example : CREATE DATABASE my_db;
• To Use a database
– Syntax : Use dbname;
– Example : Use my_db;

Creating a table
• Syntax
CREATE
TABLE table_name
(
column_name1
data_type(size),
column_name2
data_type(size),
column_name3
data_type(size),
PRIMARY
KEY(column_name1));
• Example
CREATE TABLE Persons
(
PersonID int
identity(1,1),
FirstName varchar(255),
Address varchar(255),
City varchar(255),
Primary key(PersonalID)
);

DDL - Altering a table
• ALTER TABLE Persons ADD email VARCHAR(60);
• ALTER TABLE Persons DROP COLUMN city;
• ALTER TABLE Persons CHANGE FirstName FullName
VARCHAR(20);
DDL - Deleting a Table
• DROP TABLE table_name ;

DML - Insert Data into a table
• Syntax :
– INSERT INTO table_name VALUES
(value1,value2,value3,...);
• Example:
– INSERT INTO Customers (CustomerName, City, Country)
VALUES (baabtra', ‘Calicut', ‘India');
• Note : String and date values are specified as quoted string.
Also with insert you can insert NULL directly to represent a
missing value.

DML -Retrieving information from a table
The SELECT statement is used to pull data from a table”
Syntax:
– SELECT what_to_select FROM table_name Where
conditions_to_satisfy ;
What_to_select indicates
what you want to see. This
can be a list of columns or *
to indicate “all columns”.
The Where clause is
optional. If it is present,
conditions_to_satisfy
specifies one or more
conditions that rows must
satisfy to qualify for
retrieval.

DML - Example
• Select * from person;
• Select id,firstname from person;
• Select * from person where city=‘banglore’

DML - Update Query
• Syntax:
•UPDATE table_name
SET column1=value1,column2=value2,...
WHERE some_column=some_value;
• Example:
•UPDATE Customers
SET ContactName=‘Alex', City=‘calicut'
WHERE CustomerName=‘baabtra';

Delete Query
• Syntax:
– DELETE FROM table_name
WHERE some_column=some_value;
• Example :
– DELETE FROM Customers
WHERE CustomerName=‘baabtra' AND
ContactName='Maria';

DCL – Setting Privilege
• Example:
GRANT ALL ON baabtra.user TO ‘someuser'@'somehost';
What previlages to be given
All -> will set all the
privileges
SELECT-> will set only to
select privilage
table name Username
REVOKE ALL ON baabtra.user FROM 'jeffrey'@'localhost';

Questions?
“A good question deserve a good grade…”

Self Check !!
• Attribute of an entity is represented as
– Row
– Column
– table

Self Check !!
• In ER model each entity is represented
within
– Relations/tables
– Attributes
– Schemas
– Objects

Self Check !!
• DDL is used to
– Define/Manipulate the data
– Define/Manipulate the structure of data
– Define/Manipulate the access privilege

Self Check !!
• Example for DML is
– Deleting all table data
– Creating a column
– Changing column data type

Self Check !!
• Write a query to create below table
1 Mumbai
2 Kolkata
3 Bangalore
4 Cochin
Tbl_place
• create table tbl_place
(
pk_int_id int primary key auto_increment,
vchr_place varchar(20)
);

Self Check !!
• Write a query to add one more column named “int_pin”
1 Mumbai
2 Kolkata
3 Bangalore
4 Cochin
Tbl_place
Ans: Alter table add column int_pin int;

Chapter 1 introduction to sql server

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Chapter 1 introduction to sql server