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Single column foreign key and left join - result depends from select column list

FilipFryOct 18 2013 — edited Oct 20 2013

create table test_fk(c1 date primary key deferrable);

create table test_fk1(b1 date references test_fk(c1) deferrable);

alter session set constraints=deferred;

insert into test_fk1 values(sysdate);

insert into test_fk1 values(sysdate);

insert into test_fk1 values(sysdate);

SELECT t1.C1, t.B1 FROM TEST_FK1 t LEFT JOIN TEST_FK t1 ON (t1.C1 = t.B1) WHERE t1.C1 IS NULL AND t.B1 IS NOT NULL;

C1                     B1                  

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

                       18-OCT-2013 16.38.43  

                       18-OCT-2013 16.38.48  

                       18-OCT-2013 16.38.46 

SELECT t.B1 FROM TEST_FK1 t LEFT JOIN TEST_FK t1 ON (t1.C1 = t.B1) WHERE t1.C1 IS NULL AND t.B1 IS NOT NULL;

no rows selected

Comments

EJP
is it possible to convert a PDF file to .doc and .docx by standard JDK or JRE library without using any thirdparty library?
Only if you rewrite everything that is already in the third-party libraries that you refuse to use.
if it is can anyone give me any pointer class reference to start the thing.
Not within the realm of practicality.
I need core JAVA function who will simply accept a .pdf file and convert it to .doc.
There isn't one.

There are however third-party Java PDF libraries such as iText, and MS .doc libraries such as Apache POI.

What's the aversion?
gimbal2
Answer
no one wrote:
Hi

is it possible to convert a PDF file to .doc and .docx by standard JDK or JRE library without using any thirdparty library?
No of course not. For two reasons you can reason easily for yourself

- If it is possible with core Java, why would anyone ever want to write the third party libraries as well?
- Why would core Java need to deal with proprietary file formats?

There are hundreds of file formats in existence, should core Java be able to deal with all of them? No, of course not. It is silly to even expect such a thing.
Marked as Answer by 661723 · Sep 27 2020
661723
hi

so i need to download poi-bin-3.7-20101029.tar.gz from http://poi.apache.org/download.html and install it $JAVA_HOME/ext??
Any instruction for its usage??

kind regards

Edited by: no one on Oct 5, 2011 2:04 AM
EJP
so i need to download poi-bin-3.7-20101029.tar.gz
You need to download the latest stable release
from http://poi.apache.org/download.html
from wherever you download it from
and install it $JAVA_HOME/ext??
Definitely not.* Install it whereever its instructions say, or at least on your CLASSPATH, and tell your IDE about it too.
Any instruction for its usage??
It comes with documentation. This is not an Apache POI help desk. You're asking all these questions in the wrong place.
661723
Hi

context derived to discuss on Apache POI. If you wish you may discuss other related oracle API's too I won't mind either.
:D

kind regards
EJP
I don't know what any of that means but I'm trying to help you here. You should ask in a place where the relevant expertise is congregated, and this isn't it.
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Post Details

Locked on Nov 17 2013
Added on Oct 18 2013
#column, #list, #select
11 comments
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