Problem using Oracle Object Types and Arrays.

Question

I'm currently trying to work with oracle object types in java and I'm running into some issues when trying to add an item to an array.
The basic idea is that I have a header object and a detail object (both only containing an ID and a description). Inside of my java code I'm trying to add a new detail line to the header that has been retrieved from the database.
Here's what I'm working with.
--Oracle Objects:
CREATE OR REPLACE TYPE dtl_obj AS OBJECT
    detail_id INTEGER,
    header_id INTEGER,
    detail_desc VARCHAR2(300)
CREATE TYPE dtl_tab AS TABLE OF dtl_obj;
CREATE OR REPLACE TYPE hdr_obj AS OBJECT
    header_id INTEGER,
    src VARCHAR(30),
    details dtl_tab
CREATE TYPE hdr_tab AS TABLE OF hdr_obj;
/--Java test methods
     public static void main(String[] args) throws SQLException,
               ClassNotFoundException
          // Initialize the objects
          Test t = new Test();
          t.connect(); //Connects to the database
          //The oracle connection will be accessible through t.conn
          // Create the oracle call
          String query = "{? = call get_header(?)}";
          OracleCallableStatement cs = (OracleCallableStatement) t.conn.prepareCall(query);
          cs.registerOutParameter(1, OracleTypes.ARRAY, "HDR_TAB"); //Register the out parameter and associate it with our oracle type
          int[] hdrs = { 240 }; //we just want one for testing.
          ArrayDescriptor descriptor = ArrayDescriptor.createDescriptor(
                    "ARRAY_T", t.conn);
          oracle.sql.ARRAY oHdrs = new ARRAY(descriptor, t.conn, hdrs);
          cs.setARRAY(2, oHdrs); //Set the headers to retrieve
          // Execute the query
          cs.executeQuery();
          try
               ARRAY invArray = cs.getARRAY(1);
               // Start the retrieval process
               Class cls = Class.forName(Header.class.getName());
               Map<String, Class<?>> map = t.conn.getTypeMap();
               map.put(Header._SQL_NAME, cls);
               Object[] invoices = (Object[]) invArray.getArray();
               ArrayList<Header> invs = new ArrayList(
                         java.util.Arrays.asList(invoices));
               if (invs != null)
                    for (Header inv : invs)
                         System.out.println(inv.getHeaderId() + " " + inv.getSrc());
                         t.addDetail(inv, "new line");
                         for (Detail dtl : inv.getDetails().getArray()) // Exception thrown here
//                              java.sql.SQLException: Fail to construct descriptor: Invalid arguments
//                              at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:125)
//                              at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:162)
//                              at oracle.jdbc.driver.DatabaseError.check_error(DatabaseError.java:861)
//                              at oracle.sql.StructDescriptor.createDescriptor(StructDescriptor.java:128)
//                              at oracle.jpub.runtime.MutableStruct.toDatum(MutableStruct.java:109)
//                              at com.pcr.tst.Detail.toDatum(Detail.java:40)
//                              at oracle.jpub.runtime.Util._convertToOracle(Util.java:151)
//                              at oracle.jpub.runtime.Util.convertToOracle(Util.java:138)
//                              at oracle.jpub.runtime.MutableArray.getDatumElement(MutableArray.java:1102)
//                              at oracle.jpub.runtime.MutableArray.getOracleArray(MutableArray.java:550)
//                              at oracle.jpub.runtime.MutableArray.getObjectArray(MutableArray.java:689)
//                              at oracle.jpub.runtime.MutableArray.getObjectArray(MutableArray.java:695)
//                              at com.pcr.tst.DetailTable.getArray(DetailTable.java:76)
//                              at com.pcr.tst.Test.main(Test.java:91)
                              System.out.println(dtl.getDetailDesc());
          catch (Exception ex)
               System.out.println("Error while retreiving header");
               ex.printStackTrace();
          public void addDetail(Header hdr, String desc) throws Exception
          if (hdr == null)
               throw new Exception("header not initialized");
          // Convert the current list to an ArrayList so we can easily add to it.
          ArrayList<Detail> dtlLst = new ArrayList<Detail>();
          dtlLst.addAll(java.util.Arrays.asList(hdr.getDetails().getArray()));
          // Create the new detail
          Detail dtl = new Detail();
          dtl.setDetailDesc(desc);
          // add the new detail
          dtlLst.add(dtl);
          Detail[] ies = new Detail[dtlLst.size()];
          ies = dtlLst.toArray(new Detail[0]);
          DetailTable iet = new DetailTable(ies);
          hdr.setDetails(iet);
     }I know its the addDetail method causing the issue because if I comment out the t.addDetail(inv, "new line"); call it works fine.
Message was edited by:
pcristini

Answer 1

Oracle® Database Object-Relational Developer's Guide
Also note that object relational database design is often less performant and scalable than relational. It is not very often used in production environments.
However, the object orientated programming feature that is provided with Oracle object feature set are used and can make development and interfaces a lot easier.
So in a nutshell. Say no to ref and nested table columns. Say yes to most of the other object features. IMO of course...