Tute 3 answers

Compiled by V.Y Attigala

Part Two

Use this as a Reference for the online examination

In the last tutorial we have covered the basics and little bit of member functions in this tutorial

We are going to focus deeply about methods

Create types and databases

Key points

Co Dependent Data Types

Emp_t

Mutually needed

Due to this reason

We can either create empty type and create it later

Or we can remove the dependency and alter them later

Step 1:First of all lets just create ordinary types

create type depend_t as object(

depname varchar2(20),

gender char(1),

bdate date,

relationship varchar2(10))

create type dependtb_t as table of depend_t

Dept_t Emp_t

Step 2:

now we can create emp_t

create type emp_t as object(

eno number(4),

enamee varchar2(15),

edept ref dept_t,

salaray number(8,2),

dependents dependtb_t)

Step 3:

create type dept_t as object(

dno number(20),

dname varchar2(12),

mgr ref emp_t)

create type proj_t as object (

pno number(4),

pname varchar2(15),

pdept ref dept_t ,

budget number(10,2))

create type work_t as object(

wemp ref emp_t,

wproj ref proj_t,

since date,

hours number(4,2))

create table emp of emp_t(eno primary key

)nested table dependents store as dependent_tb

See we have removed the reference because we didn’t created a one yet

Step 4 :create table dep of dept_t(dno primary key,mgr references

emp)

create table dep of dept_t(dno primary key,mgr references

emp)

create table proj of proj_t(pno primary key,pdept references

dep)

create table works of work_t(wemp references

emp,wproj references proj)

Step 5 now we have to alter back

alter table emp add constraint fk1 foreign key(edept) references dep

Question

(a)

Adding member method child allowances

alter type emp_t add member function calchild return float cascade

Thinking patern

We need

1.No of childs

2.Salary

So to get the no of salary

select salaray into sal from emp;

to get the no of childs

select count(y.depname) into noc from emp s,table(s.dependents) y;

now answer =Salary*0.05*no of childs

create or replace type body emp_t as

member function calchild

return float is

sal float;

noc integer;

begin

select salaray into sal from emp;

select count(y.depname) into noc from emp s,table(s.dependents) y;

return sal*(5/100)*noc;

end;

end;

(b)

select e.enamee,e.salaray,e.calchild() from emp e

not much to explain same theory in tutorial one

just calling the method

©

//Simple inserting method see the tutorial one

(d)

First step to alter

alter type emp_t add member function bonuscal(rate float)

return float cascade

now

its so important

we already created a member function we don’t want to destroy its body so we copy paste same + the new one like

this

for the new method

we need

Salary

Rate as a parameter

rate bonus

create or replace type body emp_t as

member function calchild

return float is

sal float;

noc integer;

begin

select salaray into sal from emp;

select count(y.depname) into noc from emp s,table(s.dependents) y;

return sal*(5/100)*noc;

end;

member function bonuscal(rate float)

return float is

sale float;

begin

select salaray into sale from emp;

return sale*rate;

end;

end;

highlighted one is the new method

e)

can be calculated using the same method call we didi in c and last tutorial its upto u guys

Bonus cal

f)

first altering to the dept_t

alter type dep_t add member function numemp

return float cascade

now we create the body

we create this for the

dept type so we haven’t written methods to dept

so completely new

create or replace type body dep_t as

member function numemp

return float is accessing a reference

nume integer;

begin

select count(p.mgr.eno) into nume from dep p;

return nume;

end;

end;

select dname,numemp() from dep where dname='academic'

This is to cover the member functions please practice this well and along with any kind of materials

Pass the examination well .

Thank you

V.Y Attigala