Giáo trình SQL bài 3

Lab 01b
Data Types – DDL – DML

1


Outlines
Data types
DDL
Create table
Alter table
Drop table

DML
Insert
Update
Delete

Faculty of Science and Technology

Database Fundamentals

2


Data types (1)
Integer
Name
bigint
int
smallint

tinyint

Bytes
Range
-263 (-9,223,372,036,854,775,808) to
8
263 - 1 (9,223,372,036,854,775,807)
4
-231 (-2,147,483,648) to
231 - 1 (2,147,483,647)
2
-215 (-32,768) to 215 - 1 (32,767)
1

Faculty of Science and Technology

0 to 255

Database Fundamentals

3


Data types (2)
Exact numeric
Name
Bytes
Range
decimal[p[,s]] 5 – 17 - 1038 +1 to 1038 - 1.
numeric[p[,s]] 5 – 17 - 1038 +1 to 1038 - 1.

p (precision)
The maximum total number of decimal digits that can be stored, both to the left and
to the right of the decimal point. The precision must be a value from 1 through the
maximum precision of 38. The default precision is 18.
s (scale)
The maximum number of decimal digits that can be stored to the right of the
decimal point. Scale must be a value from 0 through p. Scale can be specified only
if precision is specified. The default scale is 0; therefore, 0 <= s <= p. Maximum
storage sizes vary, based on the precision.
Faculty of Science and Technology

Database Fundamentals

4


Data types (3)
Appropiate numeric
Name
Float[(n)]
real

Bytes
Range
n
- 1.79E+308 to -2.23E-308,
0 and 2.23E-308 to 1.79E+308
- 3.40E + 38 to -1.18E - 38,
4
0 and 1.18E - 38 to 3.40E + 38

Faculty of Science and Technology

Database Fundamentals

5


Data types (4)
Monetary
Name
Money

Bytes
Range
8
-922,337,203,685,477.5808 to
922,337,203,685,477.5807
smallmoney
4
- 214,748.3648 to
214,748.3647

Faculty of Science and Technology

Database Fundamentals

6

Data types (5)
Date and Time
Name
datetime

Bytes
Range
8
January 1, 1753, to
December 31, 9999
smalldatetime
4
January 1, 1900, to
June 6, 2079

Faculty of Science and Technology

Database Fundamentals

7


Data types (6)
Characters
Name
char[(n)]

Bytes
Comments
0-8000 non-Unicode

varchar[(n)]

0-8000 non-Unicode

varchar(max) 0-2 GB non-Unicode, 16 bytes pointer on row,
preferred over text data type
text
0-2 GB non-Unicode, 16 bytes pointer or in
row, obsolete, varchar(max) prefered

Faculty of Science and Technology

Database Fundamentals

8


Data types (7)
Characters (contd.)
Name
nchar[(n)]

Bytes
Comments
0-8000 max 4000 unicode characters

nvarchar[(n)]

0-8000 max 4000 unicode characters

nvarchar(max) 0-2 GB 16 bytes pointer or in row, preferred
over ntext data type
ntext
0-2 GB 16 bytes pointer, obsolete,
nvarchar(max) prefered

Faculty of Science and Technology

Database Fundamentals

9


Data types (8)
Binary
Name
binary[(n)]

Bytes
0-8000

varbinary[(n)]

0-8000

Comments

varbinary(max) 0-2 GB 16 bytes pointer or in row, preferred
over image data type

Faculty of Science and Technology

Database Fundamentals

10


Data types (9)
Image
Name
Image

Bytes
Comments
0-2GB 16 bytes pointer, obsolete,
varbinary(max) prefered

Global identifier
Name
uniqueidentifier

Bytes
16

Comments

XML
Name
xml

Bytes
Comments
0-2GB 16 bytes pointer

Faculty of Science and Technology

Database Fundamentals

11


Data types (10)
Special
Name
bit
cursor
timestamp
sysname
table

Bytes
Range
1
1 byte for every 8 bit columns
0-8
8

one column per table

256
-

sql_variant 0-8016

Faculty of Science and Technology

Database Fundamentals

12


Database
CREATE DATABASE Company ON PRIMARY
( NAME = 'Company',
FILENAME = 'C:\DATA\Company.mdf' ,
SIZE = 2048KB ,
MAXSIZE = UNLIMITED,
FILEGROWTH = 1024KB )
LOG ON
( NAME = 'Company_log',
FILENAME = 'C:\DATA\Company_log.ldf' ,
SIZE = 1024KB ,
MAXSIZE = 2048KB ,
FILEGROWTH = 10%)
GO
DROP DATABASE Company
GO
Faculty of Science and Technology

Database Fundamentals

13


DDL
Create table
Alter table
Drop table

Faculty of Science and Technology

Database Fundamentals

14


Create Table (1)
CREATE TABLE
table_name
( <column_definition> [ <table_constraint> ] [ ,...n ] )
[;]
<column_definition> ::=
column_name <data_type>
[ NULL | NOT NULL ]
[ [ CONSTRAINT constraint_name ] DEFAULT constant_expression ]
| [ IDENTITY [ ( seed ,increment ) ] [ NOT FOR REPLICATION ] ]

Faculty of Science and Technology

Database Fundamentals

15


Create Table (1)
<column_constraint> ::=
[ CONSTRAINT constraint_name ]
{ { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ] |
[ FOREIGN KEY ] REFERENCES referenced_table_name [ ( ref_column ) ]
[ ON DELETE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ]
[ ON UPDATE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ]
| CHECK ( logical_expression )
}

Faculty of Science and Technology

Database Fundamentals

16


Create table (3)
< table_constraint > ::=
[ CONSTRAINT constraint_name ]
{ { PRIMARY KEY | UNIQUE } [ CLUSTERED | NONCLUSTERED ]
(column [ ASC | DESC ] [ ,...n ] )
| FOREIGN KEY ( column [ ,...n ] )
REFERENCES referenced_table_name [ ( ref_column [ ,...n ] ) ]
[ ON DELETE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ]

[ ON UPDATE { NO ACTION | CASCADE | SET NULL | SET DEFAULT } ]
| CHECK ( logical_expression )
}

Faculty of Science and Technology

Database Fundamentals

17


Example (1)
CREATE TABLE Department
(
DNumber numeric(4,0) Constraint pk_dep Primary Key,
DName varchar(15) not null,
MgrSSN char(9) Constraint fk_dep Foreign Key References
Employee(SSN),
MgrStartdate datetime,
);

Faculty of Science and Technology

Database Fundamentals

18


Example (2)
Or:

CREATE TABLE Department
(
DNumber numeric(4,0) not null,
DName varchar(15) not null,
MgrSSN char(9),
MgrStartdate datetime,
Constraint pk_dep Primary Key (DNumber),
Constraint fk_dep Foreign Key (MgrSSN) References Employee(SSN)
);

Faculty of Science and Technology

Database Fundamentals

19


Alter Table
ALTER TABLE table_name
{ ALTER COLUMN column_name
{ type_name [ ( { precision [ , scale ] } ) ]
[ NULL | NOT NULL ] | {ADD | DROP }
}
| [ WITH { CHECK | NOCHECK } ]
ADD
{ <column_definition> | <table_constraint> } [ ,...n ]
| DROP
{ [ CONSTRAINT ] constraint_name |
COLUMN column_name } [ ,...n ]
| [ WITH { CHECK | NOCHECK } ] { CHECK | NOCHECK } CONSTRAINT

{ ALL | constraint_name [ ,...n ] }
| { ENABLE | DISABLE } TRIGGER {ALL | trigger_name [ ,...n ] }
}
[;]
Faculty of Science and Technology

Database Fundamentals

20


Example (1)
Column
Adding a new column
ALTER TABLE Department ADD column_b
VARCHAR(20) NULL ;
Dropping a column
ALTER TABLE Department DROP column_b;
Changing a data type of a column
ALTER TABLE Department ALTER COLUMN
column_a NUMERIC(5,
2) ;
Database Fundamentals

Faculty of Science and Technology

21


Example (2)

Table
Primary key
ALTER TABLE Department
ADD Constraint pk_dept PRIMARY KEY (DNumber);
Foreign key
ALTER TABLE Department
ADD Constraint fk_dept Foreign Key (MgrSSN) References
Employee(SSN);
Drop Constraint
ALTER TABLE Department
DROP Constraint pk_dept;
ALTER TABLE Department
DROP Constraint fk_dept;

Faculty of Science and Technology

Database Fundamentals

22


Drop Table
DROP TABLE table_name [ ,...n ] [ ; ]
Example:
Drop table Department

Faculty of Science and Technology

Database Fundamentals

23


DML
Insert
Update
Delete

Faculty of Science and Technology

Database Fundamentals

24


Insert
Insert into table_name [(column_list)]
Values (value_list)

Example
INSERT INTO Department
VALUES (5, 'Research', '333445555', '22-MAY-78');
Or
INSERT INTO Department (DNumber, DName)
VALUES (5, 'Research');

Faculty of Science and Technology

Database Fundamentals

25