Languages And Data Types / Logical Operators Used In SQL Server
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Languages to be used:
- DDL (Data Definition language)
- DML (Data Manipulation Language)
DDL (Data Definition language) DML (Data Manipulation Language)
1.
ALTER 1.
INSERT
2.
DROP 2.
SELECT
3.
TRUNCATE 3.
UPDATE
4.
DELETE
DDL
(Data Definition Language): It is used to create
or destroy the database objects. These commands will be used by database during
the setup and removal phases of a database project.
.1ALTER : After creating a
table if we want to modify the table, we use ALTER command.
Ex. Create
database demo1 // create
a database
create table EmpDetail // create table
(
EmpId int identity(1,1), // identity is auto
generated
EmpName varchar(50),
EmpDept varchar(50),
EmpSal float
)
•Increasing the width of a column
Syntax - ALTER table EmpDetail ALTER cloumn EmpName varchar(100)
•Decreasing the width of a column :
Syntax – ALTER table EmpDetail ALTER
column EmpName varchar(50)
•Adding / Removing (Not Null / Null) constraint :
Syntax – ALTER table EmpDetail ALTER
column EmpName varchar(50) Not Null
•Adding new column :
Syntax – ALTER table EmpDetail ADD EmpPost varchar(50)
•Dropping an existing column :
Syntax – ALTER table EmpDetail DROP column EmpPost
•Adding constraint to any column :
Syntax – ALTER table EmpDetail ADD
constraint EmpId_pk //primary key
•Dropping an existing constraint :
Syntax – ALTER table EmpDetail DROP
constraint EmpId_pk
.2DROP
: If
we want to destroy the existing tables present in the database we use the DROP command.
•Dropping the table : //Remove table
Syntax – DROP table EmpDetail
3.TRUNCATE : Removes all rows from table. It is same as DELETE statement with no “where” clause.
•Truncating the table : // Move table
Syntax – TRUNCATE table EmpDetail
DML (Data Manipulating Language) : Making changes in
data that already exists.
1.
INSERT : To INSERT the values in the
column of the table.
Syntax – INSERT into
EmpDetail(EmpName,EmpDept,EmpSal)
values(Martin,EEE,10000) // if the EmpId is auto generated then no
need to generate it
2.
SELECT : To display the result or table as output we use SELECT
command.
Syntax – SELECT * from EmpDetail
3.UPDATE
: If
we want to the data existing in the table we use UPDATE statement.
Syntax – UPDATE EmpDetail Set EmpName=Mike
4DELETE : If we want to delete rows of data present in the table
we use DELETE statement.
Syntax – DELETE from EmpDetail where EmpName=Mike
Data Types And Logical Operators
Data Types Used :
1.Int
12. DateTime 23. TimeStamp
2.Bingint 13. SmallDateTime
24. Xml
3.Smallint 14. Char 25. Cursor
4.Tinyint 15. Varchar
5.Big
16. Text
6.Decimal 17. Nchar
7.Numeric 18. Nvarchar
8.Money 19. Ntext
9.Float
20. Binary
10.Real
21. Varbinary
11.Date
22. Image
Logic Operators Used :
1.ALL
6. IN
2.AND
7. LIKE
3.ANY
8. NOT
4.BETWEEN 9. OR