Connect C++ with Oracle

Shishir191's Avatar author of Connect C++ with Oracle
This is an article on Connect C++ with Oracle in C++.
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Oracle C++ Call Interface (OCCI) is an Application Programming Interface (API) that provides C++ applications access to data in an Oracle database. This API is a significant improvement to the Oracle Call Interface (OCI) API as far as ease of use is concerned. Engineers who have written JDBC (Java Database Connectivity) code will find the OCCI API to be quite similar to that of JDBC

1) The table that is used in the example code is:



Code: SQL
CREATE TABLE EMP(
    empno     NUMBER,
    ename     VARCHAR2(10),
    hireDate  Date);

2) Database Query : Select the contents of the EMP table



Code: Cpp
#include <DbManager.h>
#include <iostream>

using namespace std;

using namespace oracle::occi;

const string sqlString("select empno, ename, hiredate from emp");

const string dateFormat("DD-MON-YYYY HH24:MI:SS");

int main(int argc, char **argv)

{
    if (argc != 2)
    {
        cerr << "\nUsage: " << argv[0] << " <db-user-name>\n" << endl;
        exit(1);
    }
   
    // Initialize OracleServices
   
    DbManager* dbm = NULL;
   
    OracleServices* oras = NULL;
   
    Statement *stmt = NULL;
   
    ResultSet *resultSet = NULL;
   
    try
    {
       
        // Obtain OracleServices object with the default args.
       
        dbm = new DbManager(userName);
       
        oras = dbm->getOracleServices();
       
        // Obtain a cached connection
       
        Connection * conn = oras->connection();
       
        // Create a statement
       
        stmt = conn->createStatement(sqlString);
       
        int empno;
       
        string ename;
       
        Date hireDate;
       
        string dateAsString;
       
        // Execute query to get a resultset
       
        resultSet = stmt->executeQuery();
       
        while (resultSet->next())
        {
           
            empno = resultSet->getInt(1)// get the first column returned by the query;
           
            ename = resultSet->getString(2)// get the second column returned by the query
           
            hireDate = resultSet->getDate(3)// get the third column returned by the query
           
            dateAsString="";
           
            //You cannot check for null until the data has been read
           
            if (resultSet->isNull(1))
            {
                cout << "Employee num is null... " << endl;
            }
            if (resultSet->isNull(2))
            {
                cout << "Employee name is null..." << endl;
            }
            if (resultSet->isNull(3))
            {
                cout << "Hire date is null..." << endl;
            }
            else
            {
                dateAsString=hireDate.toText(dateFormat);
            }
            cout << empno << "\t" << ename << "\t" << dateAsString << endl;
           
        }
       
        // Close ResultSet and Statement
       
        stmt->closeResultSet(resultSet);
       
        conn->terminateStatement(stmt);
       
        // Close Connection and OCCI Environment
       
        delete dbm;
       
    }
    catch (SQLException& ex)
    {
        if (dbm != NULL)
        {
            dbm->rollbackActions(ex, stmt, resultSet); // free resources and rollback transaction
        }
    }
    catch (ExoException& ex1)
    {
        cerr << "\nCaught ExoException:\n" << ex1.getExceptionText() << endl;
        exit(2);
    }
   
    return 0;
}
like this
0
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
Nicely coded and commented.
0
seeguna's Avatar
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Good one
0
Shishir191's Avatar, Join Date: Jul 2007
Go4Expert Member
Thanks
0
pradeep's Avatar, Join Date: Apr 2005
Team Leader
Really cool! :-)
0
Shishir191's Avatar, Join Date: Jul 2007
Go4Expert Member
Thanks.
0
kush_2207's Avatar, Join Date: Jun 2007
Go4Expert Member
gr8 post !
0
Shishir191's Avatar, Join Date: Jul 2007
Go4Expert Member
Thanks.
0
kush_2207's Avatar, Join Date: Jun 2007
Go4Expert Member
Getting compile-time errors like Not able to find dbmanager.h header file....
Please Help !
Thanx.
0
Shishir191's Avatar, Join Date: Jul 2007
Go4Expert Member
Quote:
Originally Posted by kush_2207
Getting compile-time errors like Not able to find dbmanager.h header file....
Please Help !
Thanx.
Hi Kush,

Sorry for the delay. Sorry, there is no need to include "dbmanager.h" by mistake i have included it.

You have to include "occi.h" like #include<occi.h> in your program.

Note one thing more this code will not work for every compiler. Either you have to use visual C++7.
Or you can use gcc comipler version 3.4.3. If you are using gcc comipler in linux then you have to download occi libraries from Oracle web site.

And you have to copy these files into your $ORACLE_HOME/lib.
If you have installed oracle client in your machine the it contains one "rdms" folder which contain one "demo" folder . From that folder you can use "demo_xe.mk" to compile your file.

If you have any further query then you can ask me.