Storage of Java object in table column

Hello,
We have developed an application that requires some Java objects to be stored in tables.
With JDataStore, Cloudscape or InstantDB the operation is rather straightforward. We can use something like:
pstmt = conn.prepareStatement("INSERT INTO TABLEOBJ(ID,OBJ) VALUES (?,?)");
pstmt.setLong(1,i);
pstmt.setObject(2,myObject);
psmt.executeUpdate();
Some of our clients would like us to use Oracle Lite rather than any of the previously mentioned databases. The only problem is that the above simple code does not work with Oracle.
What is then the easiest way to save Java Object in table column?
Thanks in advance,
Benoit Marchal

found part of the answer in another newsgroup.
But is Oracle Lite 4.0 offering the same possibility? Is it going to be implemented in Oracle Lite 5.0?
Benoit
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Alexander Day ([email protected]):
Another little tidbit from ORacle's documentation:
"Important: The JDBC 2.0 specification states that PreparedStatement methods setBinaryStream() and setObject() can be used to input a stream value as a BLOB, and
that the PreparedStatement methods setAsciiStream(), setUnicodeStream(), setCharacterStream(), and setObject() can be used to input a stream value as a CLOB. This
bypasses the LOB locator, going directly to the LOB data itself. In the implementation of the Oracle JDBC drivers, this functionality is supported only for a configuration using an 8.1.6 database and
8.1.6 JDBC OCI driver. Do not use this functionality for any other configuration, as data corruption may result."<HR></BLOCKQUOTE>
null

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Hi
We are planing to use Toplink JPA that comes with JDeveloper 11g preview release
I have a question here!
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regards
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Solved!!!
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Object Modelling Question: How do I create multiple nested table columns in one table

Hi there,
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pelle.k wrote:
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Hi Master,
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When I try to connect to my server from an external network, I get this error: java.rmi.NoSuchObjectException: no such object in table
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Tool to create Java Object classes using the Database Tables

Hi,
Is their any tools or utility available to create the Java Object Classes using the Database Tables as input.
Lets Say I am having the Employee, Employee_Salary tables in the Database.The utility has to create the Java Object classes with the relation.
Please Help...
Thx..

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Best way for Java objects to relate to DB tables

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e.g. (rough example of what I mean)
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Thanks.

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Returning ref of table.column object.. its possible?

hello friends. see example bellow:
create type object1 is object (id number);
create table table1 (o object1, -- the collumn is object, but table not
field2 varchar2(10);
declare
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begin
-- how to do hold this ref var?????
select ref(p.o) into ref_object
from table1;
-- raise exception.
end;
Help me please.

What exactly are you trying to accomplish? To me, it looks like you are trying to select data into a user defined variable from a table. What do you mean exactly when you say you want to capture a reference (ROWID, ROWNUM, REF Cursor, etc.)?
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2   TYPE obj1 IS TABLE OF table_tipo_teste%ROWTYPE;
3   obj2 obj1;
4 BEGIN
5          SELECT tp
6                 ,nome
7    BULK COLLECT
8            INTO obj2
9            FROM table_tipo_teste;
10    FOR i IN obj2.FIRST..obj2.LAST LOOP
11      DBMS_OUTPUT.PUT_LINE( 'Data Held In Object: ' ||obj2(i).tp.id || ' ' || obj2(i).tp.nome || ' ' || obj2(i).nome
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13* END;
SQL> /
Data Held In Object: 1 Luiz Gustavo
PL/SQL procedure successfully completed.
SQL>

How to insert a java object int derby database

hi,
i have a problem , ie..i want to insert my java object int database derby.and also i need to retrieve that object from database whenever i need. Any body help me to do that in derby...
Thanks

Or you would design a table where the columns of the table correspond to attributes of the object. Then you would make a row by writing out the attributes to the columns they correspond to.

Printing out results in case of object-relational table (Oracle)

I have made a table with this structure:
CREATE OR REPLACE TYPE Boat AS OBJECT(
Name varchar2(30),
Ident number,
CREATE OR REPLACE TYPE Type_boats AS TABLE OF Boat;
CREATE TABLE HOUSE(
Name varchar2(40),
MB Type_boats)
NESTED TABLE MB store as P_Boat;
INSERT INTO House VALUES ('Name',Type_boats(Boat('Boat1', 1)));
I am using java to print out all the results by calling a procedure.
CREATE OR REPLACE package House_boats
PROCEDURE add(everything works here)
PROCEDURE results_view;
END House_boats;
CREATE OR REPLACE Package.body House_boats AS
PROCEDURE add(everything works here) AS LANGUAGE JAVA
Name House_boats.add(...)
PROCEDURE results_view AS LANGUAGE JAVA
Name House_boats.resuts_view();
END House_boats;
However, I am not able to get Results.view working in case of object-relation table. This is how I do it in the situation of relational table.
CALL House_boats.results_view();
House_boats.java file which is loaded using LOADJAVA:
import java.sql.*;
import java io.*;
public class House_boats {
public static void results_view ()
   throws SQLException
   { String sql =
   "SELECT * from House";
   try { Connection conn = DriverManager.getConnection
("jdbc:default:connection:");
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   ResultSet rset = pstmt.executeQuery();
printResults(rset);
rset.close();
pstmt.close();
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static void printResults (ResultSet rset)
   throws SQLException { String buffer = "";
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   int cols = meta.getColumnCount(), rows = 0;
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   int size = meta.getPrecision(i);
   String label = meta.getColumnLabel(i);
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buffer = buffer + label + " "; }
buffer = buffer + "\n";
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buffer = buffer + value + " "; }
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How do I print out the results correctly in my case of situation?
Thank you in advance

I have made a table with this structure:
I am using java to print out all the results by calling a procedure.
However, I am not able to get Results.view working in case of object-relation table. This is how I do it in the situation of relational table.
How do I print out the results correctly in my case of situation?
There are several things wrong with your code and methodology
1. The code you posted won't even compile because there are several syntax issues.
2. You are trying to use/test Java in the database BEFORE you get the code working outside the DB
3. Your code is not using collections in JDBC properly
I suggest that you use a different, proven approach to developing Java code for use in the DB
1. Use SIMPLE examples and then build on them. In this case that means don't add collections to the example until ALL other aspects of the app work properly.
2. Create and test the Java code OUTSIDE of the database. It is MUCH easier to work outside the database and there are many more tools to help you (e.g. NetBeans, debuggers, DBMS_OUTPUT windows, etc). Trying to debug Java code after you have already loaded it into the DB is too difficult. I'm not aware of anyone, even at the expert level, that develops that way.
3. When using complex functionality like collections first read the Oracle documentation (JDBC Developer Guide and Java Developer's Guide). Those docs have examples that are known to work.
http://docs.oracle.com/cd/B28359_01/java.111/b31225/chfive.htm
http://docs.oracle.com/cd/E11882_01/java.112/e16548/oraarr.htm#sthref583
The main issue with your example is #3 above; you are not using collections properly:
String value = rset.getString(i);
A collection is NOT a string so why would you expect that to work for a nested table?
A collection needs to be treated like a collection. You can even treat the collection as a separate result set. Create your code outside the database and use the debugger in NetBeans (or other) on this replacement code for your 'printResults' method:
static void printResults (ResultSet rset) throws SQLException {
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       ResultSetMetaData meta = rset.getMetaData();
       while (rset.next()) {
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           String ndx = rs.getString(1);
           Struct struct = (Struct) rs.getObject(2);
           System.out.println(struct.getSQLTypeName());
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           for (int j = 0; j < oa.length; j++) {
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That code ONLY deals with column 2 which is the nested table. It gets that collection as a new resultset ('rs'). Then it gets the contents of that nested table as an array of objects and prints out the attributes of those objects so you can see them.
Step through the above code in a debugger so you can SEE what is happening. NetBeans also lets you enter expressions such as 'rs' in an evaluation window so you can dynamically try the different methods to see what they do for you.
Until you get you code working outside the database don't even bother trying to load it into the DB and create a Java stored procedure.
Since your current issue has nothing to do with this forum I suggest that you mark this thread ANSWERED and repost it in the JDBC forum if you need further help with this issue.
https://forums.oracle.com/community/developer/english/java/database_connectivity
When you repost you can include a link to this current thread if you want. Once your Java code is actually working then try the Java Stored procedure examples in the Java Developer's Guide doc linked above.
At the point you have any issues that relate to Java stored procedures then you should post them in the SQL and PL/SQL forum
https://forums.oracle.com/community/developer/english/oracle_database/sql_and_pl_sql

Divide Table Column

Hello everyone.
I have run into a problem ( once again) that i want to divide the first table column
into two (but with the excepti of the column header ).
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import javax.swing.table.TableColumn;
import javax.swing.table.TableModel;
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lblTmp.setBorder(BorderFactory.createLineBorder(Color.black));
add(lblTmp);
return this;
And i prefer to use the jLabel as the renderer, since it is more light as a render, I thought.
Does anybody has any idea.
Thanks in advance for any reply.

You are taking the easy way out. I have done what you suggest since childhood, this is 65 years ago.
Thanks for your answer anyway. Have a great day.

How to store java objects in the database

Hi,
I am trying to store HttpSession state across Application Servers. Basically I am trying to build a sort of application cluster server on my own. I thought the best way to do this was to periodically store the HttpSession object from an application server in a database.
I created a table in Oracle 8i with a blob column. I use a PreparedStatement.setObject() method to store the HttpSession object in the database. My problem is, I don't know how to get the object back from the database.
Since ResultSet.getBlob returns the Blob locator, I need to read the BinaryInputStream to get all my data back. This tells me that getBlob basically works only for things like files, and cannot be used for Java objects.
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Somaiah.

Problem in truncate/drop partitions in a table having nested table columns.

Hi,
I have a table that has 2 columns of type nested table. Now in the purge process, when I try to truncate or drop a partition from this table, I get error that I can't do this (because table has nested tables). Can anybody help me telling how I will be able to truncate/drop partition from this table? IF I change column types from nested table to varray type, will it help?
Also, is there any short method of moving existing data from a nested table column to a varray column (having same fields as nested table)?
Thanks in advance.

>
I have a table that has 2 columns of type nested table. Now in the purge process, when I try to truncate or drop a partition from this table, I get error that I can't do this (because table has nested tables). Can anybody help me telling how I will be able to truncate/drop partition from this table?
>
Unfortunately you can't do those operations when a table has a nested table column. No truncate, no drop, no exchange partition at the partition level.
A nested table column is stored as a separate table and acts like a 'child' table with foreign keys to the 'parent' table. It is these 'foreign keys' that prevent the truncation (just like normal foreign keys prevent truncating partions and must be disabled first) but there is no mechanism to 'disable' them.
Just one excellent example (there are many others) of why you should NOT use object columns at all.
>
IF I change column types from nested table to varray type, will it help?
>
Yes but I STRONGLY suggest you take this opportunity to change your data model to a standard relational one and put the 'child' (nested table) data into its own table with a foreign key to the parent. You can create a view on the two tables that can make data appear as if you have a nested table type if you want.
Assuming that you are going to ignore the above advice just create a new VARRAY type and a table with that type as a column. Remember VARRAYs are defined with a maximum size. So the number of nested table records needs to be within the capacity of the VARRAY type for the data to fit.
>
Also, is there any short method of moving existing data from a nested table column to a varray column (having same fields as nested table)?
>
Sure - just CAST the nested table to the VARRAY type. Here is code for a VARRAY type and a new table that shows how to do it.
-- new array type
CREATE OR REPLACE TYPE ARRAY_T AS VARRAY(10) OF VARCHAR2(64)
-- new table using new array type - NOTE there is no nested table storage clause - arrays stored inline
CREATE TABLE partitioned_table_array
     ( ID_ INT,
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     PARTITION BY RANGE (ID_)
     ( PARTITION p1 VALUES LESS THAN (40)
     , PARTITION p2 VALUES LESS THAN(80)
     , PARTITION p3 VALUES LESS THAN(100)
-- insert the data from the original table converting the nested table data to the varray type
INSERT INTO PARTITIONED_TABLE_ARRAY
SELECT ID_, CAST(NESTED_COL AS ARRAY_T) FROM PARTITIONED_TABLENaturally since there is no more nested table storage you can truncate or drop partitions in the above table
alter table partitioned_table_array truncate partition p1
alter table partitioned_table_array drop partition p1

Storage of Java object in table column

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