Connecting c++ program with Oracle

问题

I'm trying to connect my C++ program to Oracle database(12.2).

My C++ program is (I am using g++ compiler in ubuntu),

#include <occi.h> 
#include <iostream> 

using namespace std;

int main()
{   oracle::occi::Environment *env = oracle::occi::Environment::createEnvironment();
    oracle::occi::Connection *conn = env->createConnection("bsk", "oraclepass");
    env->terminateConnection(conn);
    oracle::occi::Environment::terminateEnvironment(env);
}

I'm getting the error

undefined reference to `oracle::occi::Environment::createEnvironment(oracle::occi::Environment::Mode, void*, void* (*)(void*, unsigned long), void* (*)(void*, void*, unsigned long), void (*)(void*, void*))'
Employees.cpp:(.text+0x169): undefined reference to `oracle::occi::Environment::terminateEnvironment(oracle::occi::Environment*)'
collect2: error: ld returned 1 exit status

I'm new to database connectivity. Can you please help me with this?

回答1:

From Oracle's website, here is a valid example:

const string userName = "HR";
const string password = "password";
const string connectString = "";

Environment *env = Environment::createEnvironment();

{
   Connection *conn = env->createConnection(userName, password, connectString);
   Statement *stmt = conn->createStatement("SELECT blobcol FROM mytable");
   ResultSet *rs = stmt->executeQuery();
   rs->next();
   Blob b = rs->getBlob(1);
   cout << "Length of BLOB : " << b.length();
   ...
   stmt->closeResultSet(rs);
   conn->terminateStatement(stmt);
   env->terminateConnection(conn);
}

Environment::terminateEnvironment(env);

Your code seems to be in the right direction. So, it seems that some libraries are missing!

Again, from a different page on Oracle's website, here are the libraries required:

OCI Instant Client Data Shared Library (libociei.so on Linux and UNIX and oraociei12.dll on Windows); correct installation of this file determines if you are operating in Instant Client mode
Client Code Library (libclntsh.so.12.2 on Linux and UNIX and oci.dll on Windows)
Security Library (libnnz12.so on Linux and UNIX and orannzsbb12.dll on Windows)
OCCI Library (libocci.so.12.2 on Linux and UNIX and oraocci12.dll on Windows)

Make sure these libraries are installed on your machine.

回答2:

try this instead

$ g++ sample.C -I/opt/oracle/11.0.2/rdbms/public/ -L/opt/oracle/11.0.2/lib/ -locci -lclntsh

Replace /opt/oracle/11.0.2 with your oracle home path, it should work.

Find sample code from here

来源：https://stackoverflow.com/questions/46792046/connecting-c-program-with-oracle

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c++

Oracle

g++

database-connection

OCCI