Hai
How to insert the data into nested tables .When inserting data into nested tables i got the below error .How to drop nested tables

create type mail_add as object(address varchar2(100));

create type pre_add as object(prior_address mail_add);

create type nest_addrs as table of pre_add;

create table emp4(name varchar2(20),current_addrs mail_add,pre_add nest_addrs)
nested table pre_add store as nested_addrs return as locator


insert into emp4 values('MOHAN',mail_add('PLOT NO 24,PARAMILANAGAR'),NEST_ADDRS('SDDJSJ,SDBHJDB'));


ERROR at line 1:
ORA-00932: inconsistent datatypes


Thanks in advance

You need to use all the type constructors from top to bottom like this:

insert into emp4 values
('MOHAN',
mail_add('PLOT NO 24,PARAMILANAGAR'),
NEST_ADDRS(pre_add(mail_add('SDDJSJ')),pre_add(mai l_add('SDBHJDB')))
)


Why are you using nested tables anyway? If it is just to see how they work, fair enough. But if this is for a real database, I wouldn't use nested tables EVER. As you can see, they are hard work to use, and they violate 1st Normal Form. If your application prefers an object view, use exactly that - a view.

Hai Andrews
Thanks for your prompt reply.Nested table is used to represent a repeating group for previous addresses. Whereas a person is likely to have a small number of previous employers, most people have a larger number of previous addresses In that nested tables are used.Can you let me know if any further crons /prons about varrays also.

Thanks in advance
mohan

VARRAYs would be a worse choice for something like previous address, because they have a maximum number of elements. I can only imagine using VARRAYs and nested tables for data that would NEVER be queried in an ad hoc manner, only written/read by a procedure. Not much data is like that, and certainly previous address isn't in my view.

I would hold previous addresses in a separate (not nested) table with a foreign key to the emp table. This makes the data easily queryable in any manner, without having to "un-nest" everything. Why would you not want that?