Result Sets from Stored Procedures In Oracle

王朝oracle·作者佚名 2006-01-08

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A frequently asked question is:

I'd like to know whether ORACLE supports procedures (functions) which

returns result sets.

The answer is most definitely yes. In short, it'll look like this:

create or replace function sp_ListEmp return types.cursortype

l_cursor types.cursorType;

begin

open l_cursor for select ename, empno from emp order by ename;

return l_cursor;

end;

With 7.2 on up of the database you have cursor variables. Cursor variables are cursors opened by a pl/sql routine and fetched from by another application or pl/sql routine (in 7.3 pl/sql routines can fetch from cursor variables as well as open them). The cursor variables are opened with the privelegs of the owner of the procedure and behave just like they were completely contained within the pl/sql routine. It uses the inputs to decide what database it will run a query on.

Here is an example:

create or replace package types

type cursorType is ref cursor;

end;

create or replace function sp_ListEmp return types.cursortype

l_cursor types.cursorType;

begin

open l_cursor for select ename, empno from emp order by ename;

return l_cursor;

end;

examples for SQLPlus, Pro*C, Java/JDBC, ODBC, ADO/ASP, DBI Perl and OCI follow:

REM SQL*Plus commands to use a cursor variable

variable c refcursor

exec :c := sp_ListEmp

print c

and the Pro*C to use this would look like:

static void process()

{

EXEC SQL BEGIN DECLARE SECTION;

SQL_CURSOR my_cursor;

VARCHAR ename[40];

int empno;

EXEC SQL END DECLARE SECTION;

EXEC SQL WHENEVER SQLERROR DO sqlerror_hard();

EXEC SQL ALLOCATE :my_cursor;

EXEC SQL EXECUTE BEGIN

:my_cursor := sp_listEmp;

END; END-EXEC;

for( ;; )

{

EXEC SQL WHENEVER NOTFOUND DO break;

EXEC SQL FETCH :my_cursor INTO :ename, empno;

printf( "'%.*s', %d\n", ename.len, ename.arr, empno );

}

EXEC SQL CLOSE :my_cursor;

}

And the java to use this could be:

import java.sql.*;

import java.io.*;

import oracle.jdbc.driver.*;

class curvar

{

public static void main (String args [])

throws SQLException, ClassNotFoundException

{

String driver_class = "oracle.jdbc.driver.OracleDriver";

String connect_string = "jdbc:oracle:thin:@slackdog:1521:oracle8";

String query = "begin :1 := sp_listEmp; end;";

Connection conn;

Class.forName(driver_class);

conn = DriverManager.getConnection(connect_string, "scott", "tiger");

CallableStatement cstmt = conn.prepareCall(query);

cstmt.registerOutParameter(1,OracleTypes.CURSOR);

cstmt.execute();

ResultSet rset = (ResultSet)cstmt.getObject(1);

while (rset.next ())

System.out.println( rset.getString (1) );

cstmt.close();

}

The following is thanks to marktoml@hotmail.com (mark tomlinson)..

If you use ODBC here is a working example, but it requires the use of the

8.0.5.2.0 or later Oracle ODBC driver, and an 8.0.5 server.

' 1) Create a form with 1 Text control (Text1) and 1 List Control (List1) and

' 1 Button (btnExecute).

' 2) The only code that you need is a Click method on your button. Here is the Code.

Private Sub btnExecute_Click()

'PL/SQL Code

'===========

'CREATE OR REPLACE package reftest as

' cursor c1 is select ename from emp;

' type empCur is ref cursor return c1%ROWTYPE;

' Procedure GetEmpData(en in varchar2,EmpCursor in out empCur);

'END;

'CREATE OR REPLACE package body reftest as

' Procedure GetEmpData

'(en in varchar2,EmpCursor in out empCur) is

'begin

' open EmpCursor for select ename from emp where ename LIKE en;

'end;

Dim cn As New rdoConnection

Dim qd As rdoQuery

Dim rs As rdoResultset

Dim cl As rdoColumn

Static Number As Integer

List1.Clear

Number = 0

cn.Connect = "uid=scott; pwd=tiger; DSN=MSLANGORL;"

'enable the MS Cursor library

cn.CursorDriver = rdUseOdbc

'Make the connection

cn.EstablishConnection rdNoDriverPrompt

sSQL = "{call RefTest.GetEmpData(?,?)}"

Set qd = cn.CreateQuery("", sSQL)

qd.rdoParameters(0).Type = rdTypeVARCHAR

qd(0).Direction = rdParamInputOutput

qd(0).Value = Text1.Text

qd.rdoParameters(1).Type = rdTypeVARCHAR

'Dynamic or Keyset is meaningless here

Set rs = qd.OpenResultset(rdOpenStatic)

Debug.Print

Do Until rs.EOF

For Each cl In rs.rdoColumns

If IsNull(cl.Value) Then

List1.AddItem "(null)"

' Debug.Print " "; cl.Name; "NULL"; Error trap for

null fields

Else

List1.AddItem cl.Value

' Debug.Print " "; cl.Name; " "; cl.Value;

End If

Debug.Print

rs.MoveNext

Loop

Loop While rs.MoreResults

cn.Close

End Sub

And now, for a full ASP example (thanks to Jim Hoien and John Durst )

<%@ Language=VBScript %>

' This demonstration draws heavily from the information contained in the article at

' http://govt.us.oracle.com/~tkyte/ResultSets/index.html

' with special attention to the details provided by Mark Tomlinson.

' Make sure you have the correct Oracle ODBC driver so it will support Ref Cursors.

' This demonstration was a joint project by Jim Hoien (jhoien@yahoo.com) and John Durst (jpdurst@yahoo.com)

' These are the statements used on the Oracle server:

' /*******************************************************************************************/

' /* Create the EMP demo table and populate. (extracted from Oracle's provided demobld.sql) */

' /*******************************************************************************************/

' CREATE TABLE EMP

' (EMPNO NUMBER(4) NOT NULL,

' ENAME VARCHAR2(10),

' JOB VARCHAR2(9),

' MGR NUMBER(4),

' HIREDATE DATE,

' SAL NUMBER(7,2),

' COMM NUMBER(7,2),

' DEPTNO NUMBER(2));

' INSERT INTO EMP VALUES

' (7369,'SMITH','CLERK',7902,'17-DEC-80',800,NULL,20);

' INSERT INTO EMP VALUES

' (7499,'ALLEN','SALESMAN',7698,'20-FEB-81',1600,300,30);

' INSERT INTO EMP VALUES

' (7521,'WARD','SALESMAN',7698,'22-FEB-81',1250,500,30);

' INSERT INTO EMP VALUES

' (7566,'JONES','MANAGER',7839,'2-APR-81',2975,NULL,20);

' INSERT INTO EMP VALUES

' (7654,'MARTIN','SALESMAN',7698,'28-SEP-81',1250,1400,30);

' INSERT INTO EMP VALUES

' (7698,'BLAKE','MANAGER',7839,'1-MAY-81',2850,NULL,30);

' INSERT INTO EMP VALUES

' (7782,'CLARK','MANAGER',7839,'9-JUN-81',2450,NULL,10);

' INSERT INTO EMP VALUES

' (7788,'SCOTT','ANALYST',7566,'09-DEC-82',3000,NULL,20);

' INSERT INTO EMP VALUES

' (7839,'KING','PRESIDENT',NULL,'17-NOV-81',5000,NULL,10);

' INSERT INTO EMP VALUES

' (7844,'TURNER','SALESMAN',7698,'8-SEP-81',1500,0,30);

' INSERT INTO EMP VALUES

' (7876,'ADAMS','CLERK',7788,'12-JAN-83',1100,NULL,20);

' INSERT INTO EMP VALUES

' (7900,'JAMES','CLERK',7698,'3-DEC-81',950,NULL,30);

' INSERT INTO EMP VALUES

' (7902,'FORD','ANALYST',7566,'3-DEC-81',3000,NULL,20);

' INSERT INTO EMP VALUES

' (7934,'MILLER','CLERK',7782,'23-JAN-82',1300,NULL,10);

' /*******************************************************************************************/

' /* Create a packaged procedure that accepts a department number and returns the employees. */

' /* [Note: A standalone procedure will not work, it must be a packaged procedure!] */

' /*******************************************************************************************/

' CREATE OR REPLACE

' PACKAGE DEPARTMENT AS

' TYPE CURSOR_TYPE IS REF CURSOR;

' PROCEDURE GET_EMPS (I_DEPTNO IN NUMBER,

' O_RESULT_SET OUT CURSOR_TYPE);

' END;

' /

' CREATE OR REPLACE

' PACKAGE BODY DEPARTMENT AS

' PROCEDURE GET_EMPS (I_DEPTNO IN NUMBER,

' O_RESULT_SET OUT CURSOR_TYPE)

' AS

' BEGIN

' OPEN O_RESULT_SET FOR

' SELECT EMPNO, ENAME

' FROM EMP

' WHERE DEPTNO = I_DEPTNO;

' END;

' /

<HTML>

<HEAD>

<TITLE>Oracle ADO Test</TITLE>

</HEAD>

<BODY>

<H2>Test of ADO and Oracle Stored Procedures using Ref Cursors</H2>

Dim objConn

Dim connString

Dim cmdStoredProc

Dim param1

Dim testDeptNo

testDeptNo = 10

'testDeptNo = 20

'testDeptNo = 30

set objConn = server.createobject("adodb.connection")

' System DSN connection

' Replace the values below with your own

connString = "DSN=<YourDSN>;UID=<YourUserName>;PWD=<YourPassword>"

objConn.Open connString

Set cmdStoredProc = Server.CreateObject ("ADODB.Command")

Set cmdStoredProc.ActiveConnection = objConn

cmdStoredProc.CommandText = "Department.Get_Emps"

cmdStoredProc.CommandType = adCmdStoredProc

Set param1 = cmdStoredProc.CreateParameter ("Dept_ID", adInteger, adParamInput)

cmdStoredProc.Parameters.Append param1

param1.Value = testDeptNo

Set rs = cmdStoredProc.Execute

Response.Write ("<h3>Employees in Department # " & testDeptNo & "</h3>" & vbCrLf)

Response.Write ("<p>" & vbCrLf)

Response.Write ("<table>" & vbCrLf)

Response.Write ("<tr>" & vbCrLf)

Response.Write ("<th>Emp #</th>" & vbCrLf)

Response.Write ("<th>Name</th>" & vbCrLf)

Response.Write ("</tr>" & vbCrLf)

While (Not rs.EOF)

Response.Write ("<tr>" & vbCrLf)

Response.Write ("<td>" & rs (0) & "</td>" & vbCrLf)

Response.Write ("<td>" & rs (1) & "</td>" & vbCrLf)

Response.Write ("</tr>" & vbCrLf)

rs.MoveNext

Wend

Response.Write ("</table>" & vbCrLf)

rs.Close

objConn.Close

Set rs = nothing

Set param1 = nothing

Set cmdStoredProc = nothing

Set objConn = nothing

</BODY>

</HTML>

And the following is thanks to Brett Rosen :

I noticed that you didn't have an OCI entry

on http://osi.oracle.com/~tkyte/ResultSets/index.html .

Here is OCI code to do this (Oracle 81) if you want to include it on

that page.

Some error checking and cleanup has been removed, but the below should

work. (once dbname has been replaced appropriately)

Brett

int main(int argc, char* argv[])

{

OCIError* pOciError;

char* pConnectChar = "dbname";

char* pUsernameChar = "scott";

char* pPasswordChar = "tiger";

int answer;

OCIStmt* pOciStatement;

char* sqlCharArray = "BEGIN :success := sp_ListEmp; END;";

int id;

char ename[40];

OCIEnv* g_pOciEnvironment = NULL;

OCIServer* g_pOciServer = NULL;

OCISession* g_pOciSession = NULL;

OCISvcCtx* g_pOciServiceContext = NULL;

sb2* pIndicator=0;

sb2* pIndicator2=0;

sb2* pIndicator3=0;

OCIDefine* pOciDefine;

OCIDefine* pOciDefine2;

OCIBind* pBind;

OCIStmt* cursor;

answer = OCIInitialize(OCI_THREADED, NULL, NULL, NULL, NULL);

answer = OCIEnvInit(&g_pOciEnvironment, OCI_DEFAULT, 0, NULL);

answer = OCIHandleAlloc(g_pOciEnvironment, (void **)&pOciError, OCI_HTYPE_ERROR, 0, NULL);

answer = OCIHandleAlloc(g_pOciEnvironment, (void **)&g_pOciSession, OCI_HTYPE_SESSION, 0, NULL);

answer = OCIHandleAlloc(g_pOciEnvironment, (void **)&g_pOciServer, OCI_HTYPE_SERVER, 0, NULL);

answer = OCIHandleAlloc(g_pOciEnvironment, (void **)&g_pOciServiceContext, OCI_HTYPE_SVCCTX, 0, NULL);

answer = OCIServerAttach(g_pOciServer, pOciError, (unsigned char *)pConnectChar, strlen(pConnectChar),

OCI_DEFAULT);

answer = OCIAttrSet(g_pOciSession, OCI_HTYPE_SESSION, (unsigned char *)pUsernameChar, strlen(pUsernameChar),

OCI_ATTR_USERNAME, pOciError);

answer = OCIAttrSet(g_pOciSession, OCI_HTYPE_SESSION, (unsigned char *)pPasswordChar, strlen(pPasswordChar),

OCI_ATTR_PASSWORD, pOciError);

answer = OCIAttrSet(g_pOciServiceContext, OCI_HTYPE_SVCCTX, g_pOciServer, 0, OCI_ATTR_SERVER, pOciError);

answer = OCIAttrSet(g_pOciServiceContext, OCI_HTYPE_SVCCTX, g_pOciSession, 0, OCI_ATTR_SESSION, pOciError);

answer = OCISessionBegin(g_pOciServiceContext, pOciError, g_pOciSession, OCI_CRED_RDBMS, OCI_DEFAULT);

answer = OCIHandleAlloc(g_pOciEnvironment, (void **)(&pOciStatement), OCI_HTYPE_STMT, 0, NULL);

answer = OCIStmtPrepare(pOciStatement, pOciError, (unsigned char *)sqlCharArray, strlen(sqlCharArray),

OCI_NTV_SYNTAX, OCI_DEFAULT);

answer = OCIHandleAlloc(g_pOciEnvironment, (void **)(&cursor), OCI_HTYPE_STMT, 0, NULL);

answer = OCIBindByPos(pOciStatement,&pBind, pOciError, 1, &cursor, 0,SQLT_RSET,

pIndicator2, 0,NULL, 0,0,OCI_DEFAULT);

answer = OCIStmtExecute(g_pOciServiceContext, pOciStatement, pOciError, 1, 0, NULL, NULL,

OCI_COMMIT_ON_SUCCESS);

answer = OCIDefineByPos(cursor,&pOciDefine, pOciError,2,&id,sizeof(int),

SQLT_INT,pIndicator, 0, 0,OCI_DEFAULT);

answer = OCIDefineByPos(cursor,&pOciDefine2, pOciError,1,ename,40,

SQLT_STR,pIndicator3, 0, 0,OCI_DEFAULT);

if (answer == 0)

while ((answer = OCIStmtFetch(cursor,pOciError, 1,OCI_FETCH_NEXT,OCI_DEFAULT)) == 0)

{

printf("fetched id %d and name %s\n",id,ename);

}

answer = OCIHandleFree(pOciError, OCI_HTYPE_ERROR);

return 0;

}

And the following DBI perl example is thanks to q_richard_chen@yahoo.com (Richard Chen):

Hello Tom,

I was looking for such compilation of tips

on the topic. I did not find the section about doing

it using the popular perl DBI. After some fiddling I

get it working there too. Here is a complete working

example following your model using perl DBI. I think

it is a good idea that you include this in your howto

so that more people will benefit from it.

Thanks

Richard Chen

$ cat demo.pl

#!/usr/local/bin/perl -w

use strict;

use DBI;

use DBD::Oracle qw(:ora_types);

my $dbh = DBI->connect('dbi:Oracle:','scott','tiger') or die $DBI::errstr;

my $sth1 = $dbh->prepare(q{create or replace package types as

type cursorType is ref cursor;

end;});

$sth1->execute;

> >

$sth1 = $dbh->prepare(q{

create or replace function sp_ListEmp return types.cursorType

as l_cursor types.cursorType;

begin

open l_cursor for select ename, empno from emp order by ename;

return l_cursor;

end;});

$sth1->execute;

$sth1 = $dbh->prepare(q{

BEGIN

:cursor := sp_ListEmp;

END;

});

my $sth2;

$sth1->bind_param_inout(":cursor", \$sth2, 0, { ora_type => ORA_RSET } );

$sth1->execute();

while ( my @row = $sth2->fetchrow_array ) { print join("|",@row),"\n"; }

MFC + ODBC VERSION (example checked by Marcin Buchwald) marcin.buchwald@gazeta.pl Oracle server side code is just like in the VB example CDatabase m_DB;

BOOL ok = m_DB.OpenEx(_T("DSN=orcl;UID=velvet"),CDatabase::useCursorLib);

COraSet set(&m_DB);

set.m_Value = Text1.Text;

set.Open();

while (!set.IsEOF()) {

// set members contain values of single row

// use it here

set.MoveNext();

}

set.Close();

where

COraSet::COraSet(CDatabase* pdb) : CRecordset(pdb) {

m_nParams = 1;

m_nFields = ;

m_nDefaultType = snapshot;

}

CString COraSet::GetDefaultSQL() {

return _T("{call RefTest.GetEmpData(?,?)}");

}