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CONTENTS Introduction to DBMS

CODD rules

SQL * PLUS COMMANDS

SQL Sub Languages Operators Functions Constraints Group by, order by and having clauses

Data base objects Data dictionary in Oracle Creating users Joins Sub queries

PL/SQL

ANONYMOUS BLOCKS Cursors Triggers Procedures Functions Packages

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4

BASICS

Data

It is a collection of raw facts and figures

In order to use the data, the data needs to be preserved orstored in a definite location for every piece of data has anobjective and a purpose

Storage areas Pen drive Floppy CD ROM drive Manual storage

Data base

Place holder for storing the data to overcome the flaws with respectto data storage in the above mentioned areas

In order to store data in a data base, we need to define a datastructure Files

Tables

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5

Disadvantages with file systems

Data redundancy

Data is in secured

Data base will be dependent on the programming

logic Hardware cost was intensifying

Concurrent access anamolies

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6

Advantages with tables

In a table, rows need not be stored in a sequential manner

In a table, the data in the cells is atomic

In tables, data redundancy can be minimized or controlled

by imposing certain constraints like primary key

The usage of tables in a data base has been standardized

as relational data base management system

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Codd rules

In order to qualify a data base as RDBMS it needs

to satisfy or comply with come standards referred

to as codd rules

No of codd rules : 12

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12 Rules of Codd

1. Information rule

2. Guaranteed access rule

3. Systematic representation of null values

4. Active online catalog based on relational model

5. Data sub language rule

6. High level insert,update and delete

7. View updation rule

8. Physical data independence

9. Logical data independence

10. Data integrity rule11. Distribution rule

12. No sub version rule

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Information rule

Each and every data item must be physically

represented or stored in the form of rows and

columns in a table

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Guaranteed access rule

Each and every data item must be logically

represented as a combination of a column name,

table name and a primary key

Conclusions

In order to resolve the ambiguity in column names, we haveto use the table name in conjunction with a column name

Primary key has to be imposed on atleast 1 column in everytable for ensuring dependency between non key attributesand the primary key column so that the entire row in thattable can be uniquely identified

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Systematic representation of null

values

A null value is a value which signifies a missing

or in appropriate information in a column of a

table

Null values are independent of data type

1 null value is not equal to another null value

Null value enhance the memory management in

oracle

It has to be a default value to be supplied by thesystem in a table in case a missing information

has been encountered

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Active online catalog based on

relational model

Data dictionary has to be mandatorily

defined in any propretitory data base

package

Data dictionary is used for capturing theinformation with respect to data base

objects

Data dictionary accommodates meta data

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Views of data dictionary

All_objects

User_objects

All_views

User_views

All_sequences

User_sequences

All_triggers

User_triggers All_synonyms

User_synonyms

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High level insert, update and delete

Insert, update and delete are row wise operations

and not column wise

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Data sub language rule

Any DBMS is supposed to implement or

comply at least one of the following sub

languages to store, use and manipulate

data in a data baseData definition languageData manipulation languageTransaction control language

DDL + DML + TCL = SQL

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View updating rule

All the views that are theoretically

updatable must be practically

updated by the system

View is a virtual tableAny up dations made on a view must be

reflected on the base table and vice versa

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Physical data independence

Data base must be independent of

programming logic ie changes made

to a data base must not effect the

logic in a program

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Logical data independence

Application logic must be

independent of data base ie changes

made to a application logic must not

effect the data base

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Data integrity rule

Primary key

Unique

Check Default

Foreign key

Not null

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SQL * PLUS COMMANDS(ORACLE Proprietary)

Ch / /

Changes the old table name to new table name

Cl scr Clears the screen contents

L

Display the previous SQL command

/

Executes the previous SQL command

RUN

Display and execute the previous SQL command

I WHERE EMPNO = 7369;

Adds a new line to the previous SQL command

Save

Creates a file for the previous SQL command Extension is .SQL

Path : D:\oracle\product\10.2.0\db_1\BIN Get

Display the contents of the file created

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DESCRIPTION

SQL is a non procedural query language devised by IBM in theyear 1970 for implementing their DB product by name DB2

Using SQL queries, we cannot create a procedure or a function They are not storable in a data dictionary

SQL is a universally acceptable standard for implementingany proprietary data base

Oracle SQL server SYBASE FOX PRO MY SQL

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SUB LANGUAGES

DATA definition language(defines a data structure) Create Alter Truncate Drop

Data manipulation language(defines the way of maniuplating datain a structure)

Insert Update Delete Select

Transaction control language Grant Revoke

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Create

Create table ( )

Eg

create table stud(sno number, sname char(10));

Maximum no of characters for a table name is 30

Alter

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Alter Modify the data type of a column

Alter table modify ( );

alter table stud modify(sno varchar2(10));

You can increase the size of the column if the table is empty andcontaining data and you can decrease the size of the column if thetable is empty and the data which was previously inserted is incompliance with the decreased size of the column

Add a column

alter table stud add(city varchar2(10))

Delete a column

alter table stud drop column sname alter table stud drop (sno,age)

Drop multiple columns

Rename a column

alter table stud rename column city to state

Combinations of add and modify

alter table stud modify(state number) add (sno number)

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Data types

Number([]) Number(precision ,scale)

Date

Timestamp

Char() Varchar2()

Blob

Bfile

Clob

Insert

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Insert Inserting data into all the columns in a table Insert into stud values(10,1);

Inserting data into specific columns insert into stud(sno) values(3)

Define insertion order insert into emp1(ename,eno) values('kumar', 1)

Insert values into a table at run time insert into emp1 values(&eno,'&ename');

Insert values into a table at run time forspecific columns insert into stud(sno) values(&sno)

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Contd

Create table at run time create table &table_name(&col &data_type, &col1 &data_type1)

Truncate

Used for deleting data from the table Truncate table

Eg truncate table emp1;

Drop Drop table ;

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Update

Syntax

Update set = [where];

Eg update emp1 set ename = 'krishna' where ename = 'ravi

Deleting a value from a cell update emp1 set ename = null where eno = 7

Delete

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Delete

Delete from [where ];

Eg

delete from emp1 where eno = 1

Comparison between truncate and delete Truncate can never be rolled back Truncate is a table level command Delete can be rolled back

Delete is a row level operation

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Performance issue

Prior to deleting the table structure, the datawithin the table needs to be truncated for drop

only deletes the structure but the data within that

structure will still reside in the memory which will

go un referenced

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DESCRIPTION

SYNTAX

Select from [where ]Eg

Select * from emp;

Select sal from emp;

Select 1 from emp;

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Contd..

select empno, job from emp where sal = 1000 and

sal

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Sql operators

BETWEEN and

select sal from emp where sal between 1000 and 2000

Not between and

IN

SELECT * FROM EMP WHERE JOB IN('CLERK', 'SALESMAN','MANAGER')

NOT IN

LIKE

SELECT * FROM EMP WHERE ENAME LIKE 'S% select * from emp where ename like '_M%

DISTINCT

select distinct(job) from emp Is null

select comm from emp where comm is null /

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Concatenation operator

select ename || ' is a ' || job || ' whose salary is ' ||sal || ' from ' ||deptno from emp

Eg

SMITH is a CLERK whose salary is 800 from 20

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DESCRIPTION

A function is a sub program which accepts somearguments and returns a value

Categories of functions

System defined functions

User defined functions

Calling a function

Select function_name() from dual/;

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System defined functions

Numeric functions

String functions

Date and time functions

Conversion functions

Aggregate functions

NUMERIC FUNCTIONS

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NUMERIC FUNCTIONS

Function Description Syntax

Ceil(arg1) Returns succeeding integer

value

select ceil(0.1) from dept

Floor(arg1) Returns the preceding integer

value

select floor(-0.1) from emp

Round(arg1) Rounds the decimal to the

nearest integer value(ie 0.5

scale is taken as a standard)

select round(-1.5) from emp

Trunc(arg1) This will truncate the decimal

places and returns the integral

part

select trunc(1.34) from emp

Power(arg1,arg2) Returns the power of a number select power(2,10) from emp

Sqrt(arg1) Returns the square root of a

number

Sin.,cos,tan(arg1)

String Functions

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String Functions

Function Description Syntax

Lower(arg1) Display data in lower case select lower(ename) from emp

Upper(arg1) Display data in upper case select upper('kumar') from emp

Initcap(arg1) Display data in sentence case select initcap(ename) from emp

Substr(a1,a2,a3) A1 string, a2 startingposition of the string, a3 noof characters to be extracted

including start position

select substr(ename, 1, 3) from

emp

Concat(arg1,arg2) Combines 2 string objects select concat(45, 10) from emp

lpad

Lpad(arg1 arg2 arg3) Arg1 string object/col name SELECT LPAD(ENAME

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Lpad(arg1, arg2, arg3) Arg1 string object/col name

Arg2 no of characters to be addedfrom the left hand side + the existing noof characters

Arg3 characters to be added

SELECT LPAD(ENAME,LENGTH(ENAME)+3, 'Mr.') from emp

Rpad(arg1, arg2, arg3) Arg1

string object/col nameArg2 no of characters to be addedfrom the right hand side + the

existing no of characters

Arg3 characters to be added

SELECT rPAD(ENAME,LENGTH(ENAME)+3, 'Mr.') from emp

Ltrim(arg1, arg2) Trims characters from the left hand

side

select ltrim('hyderabad', hyd') from

emp

/

Rtrim(arg1, arg2) Trims characters from the right hand

side

select rtrim('hyderabad', bad') from

emp

/

Translate(arg1, arg2, arg3) Arg1 string, arg2 characters tobe replaced, arg3 new characters

Replace (arg1, arg2, arg3)

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Replace and translate

Replace No of characters to be replaced can be greater than or equal

to the new characters

Translate

No of characters to be replaced = no of new characters

Date and time functions

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Function Decription Syntax

Sysdate Returns the system date(dd-

mon-yy)

select sysdate+365 from emp

Add_months(arg1,arg2) Arg1 date, arg2 no ofmonths

select add_months(sysdate, -17)

from emp

Next_day(arg1, arg2) Arg1 date, arg2 day of theweek

select next_day(sysdate,

'saturday') from emp

Last_day(arg1) Arg1 date select last_day('01-feb-44') fromemp

Months_between(arg1, arg2)

Current_timestamp Display the current date and

time in milli seconds

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Aggregate functions

Sum

Avg

Count

Min

Max

Any aggregate function accepts only 1 argument

All the aggregate functions are independent of the type ofthe data to be used as an argument in those functionsexcept for sum and average.

Sum and average operate only on numeric type

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Conversion functions

To_char(arg1,arg2) select to_char(sysdate, 'dd$mon$yy') from emp

Extract select extract(year from sysdate) from emp;

To_date(arg1)

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Group by clause

select deptno, max(sal) from emp group by deptno

Note

A column which has been defined in the group by clause need not appear inthe select clause. But a column on which a aggregate function has not beeninvoked must and should appear in the group by clause

A group by clause must and should be used in conjunction with anaggregate function in the select clause

Where clause cannot be used in conjunction with a group by clause and thereplacement would be the having clause

Eg

select max(sal) from emp group by deptno having max(sal) >3000

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Order by

Display data in a sorted order Ascending Descending

Syntax

Select from order by asc/desc select * from emp order by comm

If a column has null values then

For ascending sort order, null values will be displayed at the bottom and fordescending sort order null values will be displayed at the top

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Constraints

Not null

Unique

Primary key

Check

Default

Foreign key

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Syntax for constraints imposing

Create table ( [constraint] constraint type);

Can impose constraints at 2 levels

Column level

Constraint definition and column definition apper at the same

place Table level

Constraint definition and column definition appear at differentplaces

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Not null

Discards entry of null values and permitsduplicated entries

create table B(eno number not null)

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Unique

Discards duplicated entries and permits nullvalues

create table B(eno number unique)

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Primary key

Unique and not null

Eg

create table d(eno number primary key)

Primary key and unique keys by default impose a

unique index on a column in a table

Primary key is a unique row identifier

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Check

create table e(sno number age numbercheck(age >= 18))

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Default

Create table e(sno number, doj date defaultsysdate)

insert into c values(default);

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Imposing constraints at the table level

create table c(eno number, ename varchar2(10),unique(eno))

create table d(eno number, ename varchar2(10),

primary key(eno))

Composite primary key

create table c(eno number, dno number, primarykey(eno,dno))

Composite unique key

create table d(eno number, dno number, unique(eno,dno))

create table e(eno number, ename varchar2(10),

check(eno > 1))

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Not null Unique Primary key Default Check

Not null No Yes Yes No Yes

Unique Yes No No No Yes

Primary key Yes No No No Yes

Default Yes Yes Yes No Yes

Combination of constraints on a single column of a table

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Adding a constraint

alter table e1 add primary key(eno)

Disabling a constraint

ALTER TABLE ENABLE/DISABLE CONSTRAINTTYPE

Rename a constraint

alter table e1 rename constraint e1_nn to e2_nn;

Delete a constraint

alter table e1 drop constraint e2_nn;

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Data base objects

Tables

Views

Synonyms

Sequences

Indexes

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Activities

Create

Retreive

Update

Delete

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Views

View is a virtual table

View defintion is storable and not the data from the view

Advts

User can access only specific columns of a table Up dations made on a view or on a table have to be reflected on the other

data base object Syntax

Create[or replace] view as ;

Create a view without the base table

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create force view v3 as select * from abc

Deleting a view

drop view v2 Create a view with a condition

Create view as [with check option]

View with aggregate functions

create view v1 as select max(sal) max_sal from emp3 group bydeptno

Alias name

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Contd

View with string functions create view v2 as select lower(ename) ename_ll from emp

View with numeric functions

create view v3 as select sqrt(sal) sqr_sal from emp

Read only view

create view v4 as select empno from emp3 with read only Possibilities

Create a view on a view Create a table on a view

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Synonyms

What is the difference between alias name and a synonym Alias name is temporary and used only for display purpose with respect to a

specific column in a table Synonym is a permanent name given to a table which is storable in the data

dictionary

When to use a synonym?

Synonym can be used if the name of a table is very long

Syntax

Create synonym for [] . create synonym d for emp3

Up dations made on a synonym are reflected on the base tableand vice versa

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POSSIBILITIES

Create a synonym on a view

Create a view on a synonym

Create a synonym on a synonym

Create a table on a synonym Alias name and a synonym

select eno as "Employee Number" from s6

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Sequences

It is a data base object which encourages automatic generation ofnumbers in a table

Syntax

Create sequence [start with ] [minvalue ] [maxvalue] [increment by ][cycle cache ];

Attributes of a sequence

Nextval Currval

Generate numbers from a sequence

Select .nextval/currval from /

By default, a sequence object creates a cache memory which

stores the values printed/generated by it

Contd

D fi i th t t d d l f

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Defining the start and end values of a sequence

create sequence d2 start with 100 maxvalue 200

Defining the increment value for a sequence

Defining cycle cache for a sequence

create sequence d6 start with 100 maxvalue 110 cycle cache 100

Use a sequence in a table

insert into test1 values(d7.nextval, '&ename')

Setting increment value after sequence creation

alter sequence d10 increment by 2

Setting max value after sequence creation alter sequence d10 maxvalue 100

Setting cycle cache value

alter sequence d10 cycle cache 50

Drop a sequence

Drop sequence d10;

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Sub queries

Display the salary of all the employees who are getting a salarygreater than smith

Eg

select sal from emp where sal > (select sal from emp where ename ='SMITH')

Update the salary of allen same as that of smith Display the details of all the employees who are getting a salary

greater than average salary

select * from emp where sal > (select avg(sal) from emp)

Joins

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It is a concept through which data from multiple tables can beretrieved

Joins eliminate a cross product relationship between the tables

Joins

Equi join

Retreives data from multiple tables based on the equality condition provided both the tables arerelated

Eg

* select empno, ename, dname from emp,dept where emp.deptno = dept.deptno

* select empno, ename, dname,sal from emp,dept where emp.deptno = dept.deptno

* and sal > 1000

Non equi join Right outer join

select empno, ename, dname from emp,dept where emp.deptno(+) = dept.deptno

Left outer join select empno, ename, dname from emp,dept where emp.deptno = dept.deptno(+)

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Users

Syntax Create user user name identified by password

Granting privilages

grant resource,connect to tanla;

Removing permissions revoke resource,connect from tanla;

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DESCRIPTION

It is a procedural language used in conjunction with SQL toperform some activities in a data base which are not possible

using the normal SQL queries

The implementation of PL/SQL specification is very much

benificial when compared to SQL with respect to improving the

systems performance

It reduces the network traffic in a distributed environment

The data types of SQL and PL/SQL remain the same

PL/SQL specification ensures a logical and physical data

independence

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Contents

Anonymous blocks

Cursors

Functions

Procedures Exception handling mechanisms

Triggers

Packages

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ANONYMOUS BLOCK

This block can form a single unit for combining different sets ofSQL statements so that call to be made to a data base from an

external buffer or location can be only for 1 time accomplishing

different types of results

This block cannot be permanently stored in the data dictionary

and is used only at run time

Structure of anonymous block

Declare

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Begin

;

;;

;

;

Exception when then

raise_application_error( );

End;

Output statement

Dbms_output.put_line();

The above statement can be operational if the server output isset to an on mode

Set server output on

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Display a message

begin

dbms_output.put_line('Exam to be conducted in the last session');

end;

Use the ampersand (&) operator to give any input at run time

P i h d

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Print the system date

begin

dbms_output.put_line(sysdate);end;

/

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COMMENTS

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COMMENTS

declare

date1 date; /* THIS IS A LOCAL VARIABLE */

begin

date1 := &d1;

dbms_output.put_line('The date is ' ||date1);end;

/

ADD 2 NUMBERS

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ADD 2 NUMBERS

DECLARE

N1 NUMBER;

N2 NUMBER;

N3 NUMBER;

BEGIN

N1 := &NUM1;N2 := &NUM2;

N3 := N1+N2;

DBMS_OUTPUT.PUT_LINE('THE SUM IS ' ||N3);

END;

/

DETERMINE THE BIGGEST AMONG 2

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DETERMINE THE BIGGEST AMONG 2

NUMBERSDeclare

n1 number;

n2 number;

begin

n1 := &num1;

n2 := &num2;

if(n1 > n2) thendbms_output.put_line('The biggest number is '|| n1);

else

dbms_output.put_line('The biggest number is '|| n2);

end if;

end;

P

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Program

Write an anonymous block which will perform theoperations on numbers dependending on the

users choice

If the choice is 1 then perform addition

If choice is 2 then perform subtraction

If choice is 3 then perform multiplication

Else perform division

declare

n1 number;

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n2 number;

n3 number;

begin

n1 := &num1;

n2 := &num2;n3 := &num3;

if(n1 > n2 and n1 > n3) then

dbms_output.put_line('The biggest

number is ' ||n1);

elsif(n2 > n1 and n2 > n3) then


number is ' ||n2);

else


number is ' ||n3);end if;

end;

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Accept empno at run time and display the name of that employee

declare

no number;ge number;

beginno := &num1;select age into ge from test where eno = no;dbms_output.put_line(ge);

end;

Accept the empno at run time and

d t th l f th t l b

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CONFIDENTIALMC Limited90

update the salary of that employee by

10%declare eno emp1.empno%type; sa emp1.sal%type;begin eno := &eno; select sal into sa from emp where

empno = eno; sa := sa+(10*sa/100); update emp1 set sal = sa whereempno = eno; dbms_output.put_line('Theupdated salary is '||sa);

end;/

Description Variable declaration with respect to a

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column in the table

Syntax

.% type;

%type It is an attribute which when used in conjunction with a variable name

signifies that the data type of the column in a table is in compliance withthe declared type of the variable in the anonymous block. Theadvantage of using this attribute is that if any changes are made to thetable structure, the same changes are not reflected in the applicationlogic encouraging physical data independence

Into This operator is used to copy the data from a specific column in a table into the local variable;

Syntax

* Select into from where =

A t t ti d di l th d l f th t l

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Accept empno at run time and display the name and salary of that employee

declareeno emp.empno%type;name emp.ename%type;sa emp.sal%type;

begineno := &employee_no;select ename,sal into name, sa from emp where empno = eno;dbms_output.put_line(name ||' '|| sa);

end;

Loop

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Loop

declare

x number;y number;

beginx := 1;loop

y := x*2;

insert into test10 values(x,y);x := x+1;exit when x >= 10;

end loop;dbms_output.put_line('Insertion sucessful....');

end;

For loop

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For loop

declarex number;y number;

beginx := 1;

for x in 1..10 loopy := x*2;insert into test10 values(x,y);

end loop;dbms_output.put_line('Insertion sucessful....');

end;

Requirement

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Requirement

Accept empno at run time and update the salary of an employee : If he belongs to deptno 10 then update his salary by Rs 100 If he belongs to deptno 20 then update his salary by Rs 200 If he belongs to deptno 30 then update his salary by Rs 300

declare

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declareeno emp90.empno%type;dno emp90.deptno%type;nsal emp90.sal%type;

begineno := &employee_no;select deptno,sal into dno,nsal where empno = eno;if(dno = 10) then

nsal := nsal+100;elsif(dno = 20) then

nsal := nsal+200;else

nsal := nsal+300;end if;update emp90 set sal = nsal where empno = eno;

dbms_output.put_line('Records Updated...');end;

Variables belonging to the same type cannot be declared on a single line

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Variables belonging to the same type cannot be declared on a single line

declaren1, n2 number;

begin

n1 := 10;n2 := 20;dbms_output.put_line(n1+n2);

end;/

If a value is not assigned to any local variable then by default, a null

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g y y

value will be supplied by the system

declaren number;

begin

dbms_output.put_line('The value is ' ||n);end;/

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REQUIREMENT

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REQUIREMENT

Display the names of all the employees from emptable

declare

name emp.ename%type ;

begin

select ename into name from emp;

end;

/

Description

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Description

The above code returns an error because intooperator can fetch on a maximum basis only 1

row at a time for a particular input given at run

time

To fetch multiple rows from a table, we need toimplement a specification referred to as cursors

Contd

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Contd

Cursor is a private SQL area used for fetching thedata from a table row wise ie for every SQL

statement issued by the user, by default a cursor

will be created for that statement

How the system creates a cursor

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for every SQL statement?

Declare the cursor Cursor is

Open the cursor

Open ;

Fetch data from the cursor into a local variable Fetch into ;

Close the cursor

Close ;

Display the names from the emp

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table using cursors

declare cursor c1 is select ename from emp;name emp.ename%type;

beginopen c1;loop

fetch c1 into name;exit when c1%notfound;dbms_output.put_line(name);

end loop;close c1;

end;

/

Display the first 3 rows from emp

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table

declarecursor c1 is select ename from emp;name emp.ename%type;

beginopen c1;loop

fetch c1 into name;exit when c1%rowcount >3;dbms_output.put_line(name);

end loop;close c1;

end;

Display the table itself using

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cursors

declarecursor c2 is select * from dept;rec dept%rowtype;

beginopen c2;loop

fetch c2 into rec;exit when c2%notfound;dbms_output.put_line(rec.deptno || ' ' ||rec.dname || ' '||rec.loc);

end loop;close c2;

end;/

Attributes of cursors

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Attributes of cursors

%rowtype This attribute can be used with cursors if you want to declare a variable

which holds data from multiple columns in the same table Syntax

%rowtype;

%rowcount

This attribute can be used with cursors to limit the display of data fromtables with respect to specific number of rows

%notfound

This attribute when used with cursors determines the availability of datawithin a cursor

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USER DEFINED FUNCTIONS

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USER DEFINED FUNCTIONS

SYNTAX

Create or replace () return is ;

Begin ;return ();

End []

Function to add 2 numbers

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Function to add 2 numbers

function add3(n1 number, n2 number)return number is s number;begin

s := n1+n2;return s;

end;

FUNCTION WITH DEFAULT

PARAMETERS

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PARAMETERS

Create or replace function add4(n1 number default 10, n2 number default 20)return number is s number;begin

s := n1+n2;return s;

end;

Function that accepts empno as an input and return the name

of the employee

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of the employee

create or replace function name_disp(eno emp.empno%type)return emp.ename%type is name emp.ename%type;begin

select ename into name from emp where empno = eno;

return name;end;

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Syntax

Create or replace procedure () isBegin

statements;

End;

Procedure to add 2 numbers

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Procedure to add 2 numbers

create or replace procedure add5(n1 number, n2 number, n3 out number) isbegin

n3 := n1+n2;dbms_output.put_line('The sum is ' ||n3);

end;

Description

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esc pt o

In case a parameter has been defined as an out parameter in a procedure

then that parameter has to be declared as a session variable in the SQL

prompt

SQL > VAR

Calling a procedure

SQL > exec (, , , :) In a procedure call, the out parameter has to be defined as a bind variable

Bindvariable

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Exception types

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p yp

Zero divide No_data_found

Too_many_rows

Zero divide

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_

declaren1 number;n2 number := 0;

beginn1 := &num1;dbms_output.put_line(n1/n2);

exception when zero_divide thenraise_application_error(-20001, 'sorry cannot perform division');

end;

No data found

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declareeno emp.empno%type;name emp.ename%type;

begineno := &employee_no;select ename into name from emp where empno = eno;dbms_output.put_line(name);

exception when no_data_found thenraise_application_error(-20001, 'data not available in the emp table');

end;

Too many rows

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_ y_

declarename emp.ename%type;

beginselect ename into name from emp;dbms_output.put_line(name);

exception when too_many_rows thenraise_application_error(-20001, 'see 1 row at a time');

end;/

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DESCRIPTION

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Package is a named group of functions,procedures and cursors

Advantages of using a package

Resolve ambiguity in the names of functions and procedures

Reusability

How to create a package ?

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p g

Package specification Package body

Note

Package specification name and package body name must

be the same

Syntax for creating a package

specification

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specification

Create package is;;;End;

Syntax for creating a package

body

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body

Create package body isProcedure isBegin

;

End;Function return is ;Begin

;return var;

End;

End;

Requirement

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Create a package which consists of a functionand a procedure

The function has to add 2 numbers and return the

sum

The procedure has to subtract 2 numbers

Package specification

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create package m1 isfunction sum1(n1 number, n2 number) return number;procedure sub1(n1 number, n2 number, n3 out number);end;

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Call a procedure within a package

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Exec . ()

Call a function within a package

Select . () from

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Syntax for creating a DML trigger

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Create or replace trigger of on before/after insert/update/delete for each row;Begin

raise_application_error( );End;

Restrict the users from deleting a

row from emp table

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row from emp table

create or replace trigger t1 before delete on emp for each rowbegin

raise_application_error(-20001, 'sorry cannot delete a row');

end;

Restrict the users from inserting

data into a table

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data into a table

create or replace trigger t2 before insert on result3 for each rowbegin

raise_application_error(-20001, 'do not try to insert a row');

end;

Restrict the users from creating

the table

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the table

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oracle si12

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