Download Database Management System LICT 3011

Database Management System
LICT 3011
Eyad H. Elshami
Relational DBMS objects
• RDBMS has many objects:
– Table
– View
– Synonym
– Sequence
– Index
– Procedure/Function
SQL
• Structured Query Language (SQL)
– Data Definition Language (DDL)
• Create
• Alter
• Drop
– Data Manipulation Language (DML)
• insert
• update
• Delete
– Select
Create Table
Create table TABLENAME(
Col1Name
Col2Name
Col3Name
.
.
.
ColxName
);
datatype
datatype
datatype
constraint
constraint
constraint
default,
default ,
default,
datatype
constraint
default
Data types
Data Type
Use to store
number(n)
number(p, s)
an integer number within size n digits
char(n)
varchar2(n)
date
raw
Long raw
a fixed length character
BLOB
binary file with size 4G
a real number within size p digits s of them after
the floating point.
a variable length character
date and time
binary data file with size 2000B
binary file with size 2G
Constraints
• Not null
– Attribute could not be empty
• Unique
– Attribute value could not be duplicated
• Check
– Attribute value must satisfies some condition
• Primary key
– Attribute value satisfies not null, unique, and indexing
• Foreign key (reference)
– Attribute value must be in the reference table
Create table example
Create Table College(
CID
Cname
);
number(2) primary key,
varchar2(25) unique not null
Create table example
Create table students(
SID
number(5) primary key,
Sname
varchar2(25) not null,
Sgender char(1) default ‘m’ check(Sgender in(‘m’,’f’)),
Sbdate
date,
CID
number(2) references College(CID),
Saverage
);
number(5,2)
Alter Table
• Alter Table TableName
– Add ColumnName datatype default Constraint;
– Add Constraint ConstraintName ConstrainType;
– Modify ColumnName newdatatype;
– Drop column ColumnName;
– Drop Constraint ConstraintName;
Alter Examples
• Alter table students
add Sphoto long raw;
__________________________________
• Alter table students
modify sname varchar2(20);
_________________________________
• Alter table students
drop column sphoto;
Alter Examples
• Alter table students
add constraint sname_u unique(sname);
__________________________________
• Alter table students
drop constraint sname_u;
_________________________________
http://itc-shami.iugaza.edu:5560/isqlplus/
Create User, change you password
• create user UserName
identified by Password
default tablespace users
temporary tablespace temp;
• alter user UserName
identified by Newpassword;
Grant privileges to user
Grant srole, unlimited tablespace
to USERNAME;
Change you password
• alter user UserName
identified by Newpassword;
Describe a table
• describe tablename
To see the tables name
–Select * from tab;