Storing Objects in DB2 - DB2 Database

Rhino

Is it possible to store Java objects in DB2 V8.2 for Windows/Unix/Linux via
JDBC?

Specifically, if I have a 4-dimensional boolean array, i.e. boolean[][][][],
can I store it directly in a column of a DB2 table? If so, how do I do it?

It would be VERY convenient if I could store this boolean array directly in
a column of a DB2 table but I'm not at all clear on whether this is
possible, even after reading the documentation in the Information Center. I
was intrigued by the setObject() and getObject() methods in JDBC but I'm not
at all sure if I can use them for the purpose I described. I'm especially
unlclear about what datatype the column containing the Object could/should
be.

If I can't store a multidimensiona l boolean array directly in a table
column, I can always convert it into a representation of the array that uses
more traditional datatypes. For instance, I could convert:

boolean[] myArray = {true, false, true};

into this String:

String myString = "TFT"; //T=true; F=false

then store the String representation of the array in one of the CHAR column
types. But it would be much more convenient if I could simply store the
boolean[][][][] array directly in a column of the table. Does anyone know if
that is possible? If it is, a brief code snippet showing how to insert the
value would be VERY helpful!

--
Rhino

Jul 4 '06 #1

Subscribe Reply

3713

Hardy

It seems to be a programming strategy other than a database one. you
cannot do what you want without further coding. maybe some UDT will be
helpful and you can balance the effort on the java and UDF.
Rhino å†™é“ï¼š

Is it possible to store Java objects in DB2 V8.2 for Windows/Unix/Linux via
JDBC?

Specifically, if I have a 4-dimensional boolean array, i.e. boolean[][][][],
can I store it directly in a column of a DB2 table? If so, how do I do it?

It would be VERY convenient if I could store this boolean array directly in
a column of a DB2 table but I'm not at all clear on whether this is
possible, even after reading the documentation in the Information Center.I
was intrigued by the setObject() and getObject() methods in JDBC but I'm not
at all sure if I can use them for the purpose I described. I'm especially
unlclear about what datatype the column containing the Object could/should
be.

If I can't store a multidimensiona l boolean array directly in a table
column, I can always convert it into a representation of the array that uses
more traditional datatypes. For instance, I could convert:

boolean[] myArray = {true, false, true};

into this String:

String myString = "TFT"; //T=true; F=false

then store the String representation of the array in one of the CHAR column
types. But it would be much more convenient if I could simply store the
boolean[][][][] array directly in a column of the table. Does anyone knowif
that is possible? If it is, a brief code snippet showing how to insert the
value would be VERY helpful!

--
Rhino

Jul 4 '06 #2

Rhino

Are you saying that it is definitely NOT possible to store a boolean array
directly in a DB2 table?

If it isn't possible to store the array directly, I can transform it into
something that can be stored and I'm not too worried about writing the code.
I'm mostly just trying to be 100% sure that there is no way to store the
array directly.

--
Rhino
"Hardy" <wy****@gmail.c omwrote in message
news:11******** **************@ j8g2000cwa.goog legroups.com...
It seems to be a programming strategy other than a database one. you
cannot do what you want without further coding. maybe some UDT will be
helpful and you can balance the effort on the java and UDF.
Rhino ??:

Is it possible to store Java objects in DB2 V8.2 for Windows/Unix/Linux
via
JDBC?

Specifically, if I have a 4-dimensional boolean array, i.e.
boolean[][][][],
can I store it directly in a column of a DB2 table? If so, how do I do it?

It would be VERY convenient if I could store this boolean array directly
in
a column of a DB2 table but I'm not at all clear on whether this is
possible, even after reading the documentation in the Information Center.
I
was intrigued by the setObject() and getObject() methods in JDBC but I'm
not
at all sure if I can use them for the purpose I described. I'm especially
unlclear about what datatype the column containing the Object could/should
be.

If I can't store a multidimensiona l boolean array directly in a table
column, I can always convert it into a representation of the array that
uses
more traditional datatypes. For instance, I could convert:

boolean[] myArray = {true, false, true};

into this String:

String myString = "TFT"; //T=true; F=false

then store the String representation of the array in one of the CHAR
column
types. But it would be much more convenient if I could simply store the
boolean[][][][] array directly in a column of the table. Does anyone know
if
that is possible? If it is, a brief code snippet showing how to insert the
value would be VERY helpful!

--
Rhino

Jul 4 '06 #3

Serge Rielau

Rhino wrote:

Are you saying that it is definitely NOT possible to store a boolean array
directly in a DB2 table?

If it isn't possible to store the array directly, I can transform it into
something that can be stored and I'm not too worried about writing the code.
I'm mostly just trying to be 100% sure that there is no way to store the
array directly.

DB2 does not support an ARRAY data type.
If all you want is store (you don't want to operate on it in DB2) then
you should linearize the array into a VARCHAR FOR BIT DATA or a BLOB (if
it's big). In C I would simply cast the beast to a char pointer and be
done with it. Not sure if there is anything similar brute but efficient
in Java :-)

Cheers
Serge
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

IOD Conference
http://www.ibm.com/software/data/ond...ness/conf2006/

Jul 4 '06 #4

Rhino

"Serge Rielau" <sr*****@ca.ibm .comwrote in message
news:4g******** *****@individua l.net...

Rhino wrote:
>Are you saying that it is definitely NOT possible to store a boolean
array directly in a DB2 table?

If it isn't possible to store the array directly, I can transform it into
something that can be stored and I'm not too worried about writing the
code. I'm mostly just trying to be 100% sure that there is no way to
store the array directly.
DB2 does not support an ARRAY data type.

I knew that :-)

I was wondering if there was some way to store an Object though. If I could
stuff the boolean array into an Object, that would probably meet the users
needs. Being able to store the array directly would be even better, of
course, but that sounds like it's impossible.

By the way, do you have any idea when/if DB2 will support the ARRAY
datatype? Is it in Version 9 by any chance?

If all you want is store (you don't want to operate on it in DB2) then you
should linearize the array into a VARCHAR FOR BIT DATA or a BLOB (if it's
big). In C I would simply cast the beast to a char pointer and be done
with it. Not sure if there is anything similar brute but efficient in Java
:-)

I can manage to linearize it easily enough with a little Java code. I just
wanted to see if there was any way to store it without having to linearize
and de-linearize it.

--
Rhino

Jul 4 '06 #5

Serge Rielau

Rhino wrote:

By the way, do you have any idea when/if DB2 will support the ARRAY
datatype? Is it in Version 9 by any chance?

Not in DB2 9. And if you want to know what's in Python you'll need an
NDA and sign your name in blood.
Can you define what you mean by an object? If you can pass DB2 the java
object in binary format it'll gladly store that.

Cheers
Serge
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

IOD Conference
http://www.ibm.com/software/data/ond...ness/conf2006/

Jul 4 '06 #6

Gregor KovaÄ

Serge Rielau wrote:

Rhino wrote:
>By the way, do you have any idea when/if DB2 will support the ARRAY
datatype? Is it in Version 9 by any chance?
Not in DB2 9. And if you want to know what's in Python you'll need an
NDA and sign your name in blood.
Can you define what you mean by an object? If you can pass DB2 the java
object in binary format it'll gladly store that.

Cheers
Serge

Yep, usually (but unfortunattely not for all Java classes) you can serialize
an object in java and you get an array of bytes, which you can put into a
BLOB or VARCHAR FOR BIT DATA.

Best regards,
Kovi
--
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
| Gregor Kovac | Gr**********@mi kropis.si |
~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~ ~~~~
| In A World Without Fences Who Needs Gates? |
| Experience Linux. |
-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-

Jul 5 '06 #7

Rhino

"Gregor Kovac" <gr**********@m ikropis.siwrote in message
news:2X******** ************@ne ws.siol.net...

Serge Rielau wrote:

>Rhino wrote:
>>By the way, do you have any idea when/if DB2 will support the ARRAY
datatype? Is it in Version 9 by any chance?
Not in DB2 9. And if you want to know what's in Python you'll need an
NDA and sign your name in blood.
Can you define what you mean by an object? If you can pass DB2 the java
object in binary format it'll gladly store that.

Cheers
Serge

Yep, usually (but unfortunattely not for all Java classes) you can
serialize
an object in java and you get an array of bytes, which you can put into a
BLOB or VARCHAR FOR BIT DATA.

Thanks Gregor, I think you've just answered my question. It sounds like I
always need to convert all but the simplest of Objects to byte arrays for
storage in BLOBs or VARCHAR FOR BIT DATA columns. The only things I don't
need to convert to byte arrays are integers, doubles, floats,
dates/times/timestamps, and Strings: those can be stored directly in the
corresponding DB2 datatypes.

--
Rhino

Jul 5 '06 #8

Rhino

"Serge Rielau" <sr*****@ca.ibm .comwrote in message
news:4h******** *****@individua l.net...

Rhino wrote:
>By the way, do you have any idea when/if DB2 will support the ARRAY
datatype? Is it in Version 9 by any chance?
Not in DB2 9. And if you want to know what's in Python you'll need an NDA
and sign your name in blood.

It's okay, I wasn't trying to find out anything that hadn't already been
revealed :-) I just thought there might have been some kind of announcement
about a general strategic direction with respect to datatype support for
coming versons of DB2.

Can you define what you mean by an object? If you can pass DB2 the java
object in binary format it'll gladly store that.

Virtually everything in Java is an Object. In fact, the only things that
aren't Objects are the primitives: short, int, long, boolean, char, and one
or two others. And even the primitives have wrapper classes that can turn
them into Objects. So pretty much anything you can imagine is an Object: a
File, a URL, a ResultSet, an Image, GUI components, etc. etc. etc.

I suppose I was just dreaming the impossible dream but when I saw methods
setObject() and getObject() it occurred to me it might mean that _any_ Java
Object might be storable in and retrievable from DB2 _DIRECTLY_. Then,
instead of having to linearize the data into a byte stream for the insert
and then convert it back when I read the data, I could just store it in its
original form and get it back that same way.

Naturally, I looked at the Java API and the DB2 documentation on setObject()
and getObject() but I found them very vague and they didn't answer the
question of whether they worked the way that I would have liked them to
work. But it now seems pretty clear that they DON'T work the way I wanted.

It struck me that my impossible dream might be something that DB2 will be
doing somewhere down the road and might even have been announced at some
point; I could have easily missed such an announcement. That's why I asked
whether it was coming in Viper or further down the road.

I'm going to hold on to a vague hope that direct storage of any Object in a
DB2 table will be possible some day but I'm going to make sure that I don't
expect "some day" to be any time soon :-)

In the meantime, I will convert Objects to byte arrays as I currently do
with JPGs or audio files. This is not really a problem. It would just be
that much more convenient if I didn't have to convert to or from byte arrays
to store and use my Objects.

--
Rhino

Cheers
Serge
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

IOD Conference
http://www.ibm.com/software/data/ond...ness/conf2006/

Jul 5 '06 #9

Serge Rielau

Rhino wrote:

"Serge Rielau" <sr*****@ca.ibm .comwrote in message
news:4h******** *****@individua l.net...
>Rhino wrote:
>>By the way, do you have any idea when/if DB2 will support the ARRAY
datatype? Is it in Version 9 by any chance?
Not in DB2 9. And if you want to know what's in Python you'll need an NDA
and sign your name in blood.

It's okay, I wasn't trying to find out anything that hadn't already been
revealed :-) I just thought there might have been some kind of announcement
about a general strategic direction with respect to datatype support for
coming versons of DB2.

One new data type that you can look forward to is a decimal floating
point type. That cat is out of the bag.

Cheers
Serge
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

IOD Conference
http://www.ibm.com/software/data/ond...ness/conf2006/

Jul 5 '06 #10

Similar topics

2603

Storing objects in Session Variables - exactly why not?

by: mjkahn | last post by:

I've read (and read!) that you shouldn't store objects in Session variables. I've read these reasons: - The object takes up memory that may not be freed until the session times out. Better to create the object only when you actually use it. - Causes poor performance because the thread that created the object has to service all requests for it. Assuming I can live with the memory and performance implications (a big if,

ASP / Active Server Pages

2249

Storing objects in a union

by: Ann Huxtable | last post by:

Hi, I am writing a nested table structure to mimic data returned from a database (actually, a heirarchical recordset). I am representing the cells where the actual data is stored, by a union: class Cell { union { char* s ; //std::string s ;

C / C++

2582

Storing objects in vectors - what's wrong with this code?

by: Alfonso Morra | last post by:

I have written the following code, to test the concept of storing objects in a vector. I encounter two run time errors: 1). myClass gets destructed when pushed onto the vector 2). Prog throws a "SEGV" when run (presumably - attempt to delete deleted memory. Please take a look and see if you can notice any mistakes I'm making. Basically, I want to store classes of my objects in a vector. I also have three further questions:

C / C++

3956

Storing objects in a vector

by: Alfonso Morra | last post by:

I have the ff code for testing the concept of storing objects: #include <vector> #include <iostream> using namespace std ; class MyClass { public: MyClass(){

C / C++

3080

Storing objects in SQL Server table

by: Diego F. | last post by:

Hello. I need to store custom objects in a SQL Server 2000 table. Which is the easiest way to do it? Do I need to write methods to store each attribute separately from C# app to the table and the opposite as well? Regards, Diego F.

C# / C Sharp

2000

What's the current wisdom on storing objects in the Application Variable?

by: Frank Rizzo | last post by:

In classic ASP, it was considered a bad idea to store VB6-created objects in the Application variable for various threading issues. What's the current wisdom on storing objects in the Application variable in ASP.NET? I am thinking of storing several objects there, not too large, so there won't be any memory issues or anything like that. Is ASP.NET still subject to threading issues?

ASP.NET

2178

Storing objects (classes) in Session in ASP.NET 2

by: Mark Rae | last post by:

Hi, This relates to the previous thread "Disappearing Sessions", but is a bit more generic so I thought I'd start a new thread. This one relates to the storing of objects in Session once only to prevent the system having to constantly query the database for the same information. I'm currently upgrading a v1.1 app to v2 (that's all I seem to do these days!), and it contains a class called CUser which holds details of the currently...

ASP.NET

7302

Best practice : storing objects in session-variables ?

by: david | last post by:

I have a class with some business-logic and with every roundtrip, I need an instance of this class, so I have to create it, every time again. That doesn't seem very efficient. I thought it would be 'better' to store an instance of this class in a session-variable, so it's available all the time and needs to be instanced only once. Is this, generally speaking, a good idea, storing objects in session-variables ? Do you guys ever use this...

ASP.NET

2178

Storing objects into a generic list.

by: Miesha.James | last post by:

Hello, I'm trying to rewrite visual c++ code into visual c++ .NET code and I've run across a problem with storing objects into a list. Here;s an example of the code I have: ref struct Cookies { String^ Name;

.NET Framework

3060

Storing objects in relational database

by: nayden | last post by:

I started playing with python a few weeks ago after a number of years of perl programming and I can say that my first impression is, unsurprisingly, quite positive. ;) The reason I am writing here is that I can't seem to figure out how to save/restore python objects into a relational database. The way I used to do it in perl was to 'freeze' the object before storing it into the database and 'thaw' it before restoring it. (For those not...

Python

9663

What is ONU?

by: marktang | last post by:

ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...

General

10404

Problem With Comparison Operator <=> in G++

by: Oralloy | last post by:

Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...

C / C++

10193

Maximizing Business Potential: The Nexus of Website Design and Digital Marketing

by: jinu1996 | last post by:

In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...

Online Marketing

7525

Access Europe - Using VBA to create a class based on a table - Wed 1 May

by: isladogs | last post by:

The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...

Microsoft Access / VBA

6761

Couldn’t get equations in html when convert word .docx file to html file in C#.

by: conductexam | last post by:

I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...

C# / C Sharp

5415

Trying to create a lan-to-lan vpn between two differents networks

by: TSSRALBI | last post by:

Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...

Networking - Hardware / Configuration

5548

Windows Forms - .Net 8.0

by: adsilva | last post by:

A Windows Forms form does not have the event Unload, like VB6. What one acts like?

Visual Basic .NET

4089

transfer the data from one system to another through ip address

by: 6302768590 | last post by:

Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system

C# / C Sharp

2906

Comprehensive Guide to Website Development in Toronto: Expert Insights from BSMN Consultancy

by: bsmnconsultancy | last post by:

In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

General