returning a result set from a java stored procedure through SQL “select * from ”

Question

Can I get the result from a java stored procedure (oracle) directly through an SQL select * from statement ?

On the database I would have a java stored procedure / function, which when it called returns a multi-column, multi-row result set.
I would like to access these results directly through a select * from [table] statement.

So the java stored procedure should behave like a table.
In MySQL the following should be possible (but not java stored procedures): SELECT col1 FROM (EXEC proc1)

Is this possible in oracle where proc1 is a java stored procedure?

Answer 1

This answer on a different forum may help you.

Look at the sample in the bottom of the message to see how to select from a collection returned by a Java method ( that may also be a Java Stored Procedure).

Here is a sample on how to do it with Java Stored Procedure

1) Create DB object to define the type of the returned rows:

create type try_obj as object (
        field_a number,
        field_b varchar2(10)
    )
/

create type try_obj_tab as table of try_obj
/

2) Create the Java class on the DB with a static method(GetSampleResult) that returns a Collection

create or replace and compile java source named QueryReturn as
import java.sql.*;
import java.util.*;

import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;
import oracle.sql.*;


public class QueryReturn implements ORADataFactory,ORAData{
    private NUMBER field1;
    private CHAR field2;

    public QueryReturn(OracleConnection conn,int n,String c) throws SQLException {
        field1 = new NUMBER(n);
        field2 = new CHAR(c,oracle.sql.CharacterSet.make(conn.getStructAttrCsId()));
    }

    public QueryReturn(NUMBER n, CHAR c) {
        field1 = n;
        field2 = c;
    }
    public QueryReturn(Object[] attributes) {
        this(
                (NUMBER) attributes[0],
                (CHAR) attributes[1]
            );
    }
    public QueryReturn(Datum d) throws SQLException {
        this(((STRUCT) d).getOracleAttributes());
    }

    public ORAData create(Datum d, int sqlType) throws SQLException {
        if (d == null)
            return null;
        else {
            return new QueryReturn(d);
        }
    }

    public STRUCT toSTRUCT(Connection conn) throws SQLException  {
        StructDescriptor sd =
            StructDescriptor.createDescriptor("TRY_OBJ", conn);
        Object [] attributes = { field1,field2 };
        return new STRUCT(sd, conn, attributes);
    }
    public Datum toDatum(Connection conn) throws SQLException {
        return toSTRUCT(conn); 
    }


    public static ARRAY GetSampleResult() throws SQLException, ClassNotFoundException {
        // initialize the connection
        OracleConnection conn = null;
        conn = (OracleConnection) (new oracle.jdbc.OracleDriver()).defaultConnection();

        // create the return java array
        // There will be two Rows
        //  1   abc
        //  2   dce
        QueryReturn javaArray[] = {
                new QueryReturn(conn,1,"abc"),
                new QueryReturn(conn,2,"dce")
            };

        // Map the java class to the Oracle type
        Map map = conn.getTypeMap();
        map.put("TRY_OBJ", Class.forName("QueryReturn"));
        ArrayDescriptor jTryObjArrayDesc = ArrayDescriptor.createDescriptor (
                "TRY_OBJ_TAB",
                conn
            );


        // create an Oracle collection on client side to use as parameter
        ARRAY oracleCollection = new ARRAY(jTryObjArrayDesc,conn,javaArray);

        return oracleCollection;
    }
}

3) Create the Wrap to use Java Stored Procedure in a function

create or replace function GetSampleResult 
    return try_obj_tab
AS LANGUAGE JAVA
    NAME  'QueryReturn.GetSampleResult()  return oracle.sql.ARRAY';

4) Show the result

SQL> select *
  2  from table(GetSampleResult())
  3  /

   FIELD_A FIELD_B
---------- ----------
         1 abc
         2 dce

SQL>

Answer 2

Write a SSP (SQL Stored Procedure) to call JSP (Java Stored Procedure), and then use that SSP in your query. Simple eh.

Further, take a look at CallableStatement .

Answer 3

I have never used it in combination with Java calling the stored procedure but my guess is it should be possible to use the 'pipelined' functionality in recent Oracle databases.

See here or Google/Bing for it to learn more.

Answer 4

Tom Kyte说：“ 你不能将java存储过程的结果集返回给plsql。 ”

Answer 5

I'm afraid it is not possible. But if your database supports functionality of selecting data from stored procedure in way you mentioned, you can create a view and select from it.

Anyway Oracle can return resultset from a stored procedure and you can access it from Java. See this link