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;
}
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