الوحدة التاسعة - قاعدة البيانات وادارتها

قاعدة البيانات وادارتها

Data Type:

Char (n): حرف255–سلسلة رمزية محددة الطول مسبقا

Varchar2 (n): حرف 2000–سلسلة رمزية طول النص فيها هو الي يحدد طولها

Number(n,m):

m: الطول االجمالي للرقم.

n: طول الكسور

Ex: 102.52 = Number(6,2).

Date: شهر / وقت / يوم / تاريخ..

أوامر لغة وصف وتعريف البياناتData Definition Language (DDL)

Command

AbdulRahman M.Baraka

Tables:

Create table tablename (Column_Name type(size) [null/notnull]) Create table Dep(DNo number(3) not null, Dname varchar2(12));

DESC table_name (describe the table).

Alter table tablename Add (NewColumn_Name type) Alter table Dep Add (DCom number(3.2));

Alter table tablename Modify (Column_Name type(New length)) Alter table Dep Add (DCom number(6.2));

Alter table tablename Rename OldColumn_Name NewColumn_Name; Alter table Dep Rename (DCom Com)

Drop table tablename; Drop table Dep;


Command


Keys:

Primary key: Create table Emp(ENo number(3) Primary Key);

Create table Emp(ENo number(3), Ename varchar2(12),Constraint Emp_PK primary key(ENo);

Alter table Emp Add Constraint Emp_PK primary key (ENo);

Foreign key: Create table Emp(ENo number(3), DepNo number(3),

Constraint Emp_FK foreign key(DepNo) references Dept(DepNo);

Alter table Emp Add Constraint Emp_FK foreign key (DepNo) references Dept(DepNo);


Command


Check Constraints:

Create table Emp(ENo number(3) Primary Key, Age number(2)CHECK (age between 18 to 70));

Create table Emp(ENo number(3) Primary Key, Marital_Statusvarchar2(1) default ‘s’ CHECK (Marital_status in (‘s’, ‘m’, ‘d’, ‘w’));

Alter table Emp Add Constraint Emp_id Unique (EID);


Command


Indexes:

Create index index_name On table_name(column_name)

Create index std_name_Indx On student(std_name);

Views:

Create view view_name AS select statements.

Create view emp_EA AS select * from emp where dep_no=10;


Command


Insert:

Insert into table_name ( column1, column2 …) Values (value1,…);

Insert into student( st_no,st_name) Values (501,’Ali’);

Update:

Update table_name Set column_name = new_value Where Condition;

Update student Set st_age=22 Where st_no=501;

Delete:

Delete From table_name Where Condition;

Delete From student Where st_no=501;

أوامر لغة معالجة البياناتData Manipulation Language (DML)

Command


Select Statement:

SELECT {DISTINCT} Columns

FROM Table_name

WHERE Conditions

{ORDER BY [DESC/ASC]}

--------------------------------------

Select * FROM Student

SELECT Sname FROM Student

SELECT SID,Sname FROM Student.

SELECT Sname FROM Student WHERE Age<20

(SQL)البنية األساسية للغة التساؤل البنيوي


Functions of Select Statement:

Count:

SELECT COUNT(*) FROM Student WHERE St_Avg>80;

Avg:

SELECT COUNT(*), AVG(Sage) FROM Student WHERE St_Avg>80;

SUM:

SELECT SUM(E_Salary) FROM Emp WHERE E_Dep=5 ;

Max, Min:

SELECT MAX(E_Salary),MIN(E_Salary) FROM Emp WHERE E_Dep=5 ;

Aliases:

SELECT Ename EmployeeName FROM Emp;



Parameters:

Like:

SELECT Sname FROM Student WHERE Sname like’A%’;

Between:

SELECT Ename FROM Emp WHERE ESal BETWEEN 300 AND 500;

In:

SELECT Ename FROM Emp WHERE EDep IN (12,15);

Null:

SELECT Ename FROM Emp WHERE Tel IS NULL;



Security:

Create/Drop user: Create user user_name identified by password.

Create user guest1 identified by free;

Grant connect, resource to user_name.

Grant connect, resource to guest1;

Permissions: Grant < Select/Insert/Delete/Update> ON <table> TO <users>.

Grant select ON Employee TO Ali.

Revoke < Select/Insert/Delete/Update> ON <table> TO <users>.

Revoke insert ON Employee TO Mona.



Rollback: Insert into student Values (501,’Reem’,7,20);

ROLLBACK;


SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

Student

SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

501 Reem 7 20

SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

501 Reem 7 20

Student Student


Rollback: Insert into student Values (501,’Reem’,7,20);

COMMIT;

ROLLBACK;


SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

Student

SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

501 Reem 7 20

SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

501 Reem 7 20

Student Student

SID Sname Rate Age

0102 Ali 8 18

0106 Khalid 3 22

0107 Mona 2 23

501 Reem 7 20AbdulRahman M.Baraka

الوحدة التاسعة - قاعدة البيانات وادارتها

Education