Perl Cd Bookshelf [Electronic resources] نسخه متنی

Initializing the C++ Database XML Application

The first step when creating a C++ database application is to perform all of the necessary OCI initializations and allocations. These steps are required for all OCI applications, as the following code illustrates. This init_env_handle() function creates and initializes the OCI environment that requires an allocation of several handles that will be populated by the subsequent member functions. This function is not application-specific and thus can be used as-is in your applications.

/*--------------------------------------------------------*/

 /* Initialize the environment and allocate handles */ 
/*--------------------------------------------------------*/  
sb4 ociapi::init_env_handle() 
{ sword status = 0;  
/* Environment initialization and creation */ 
if (OCIEnvCreate((OCIEnv **) &envhp, (ub4) OCI_OBJECT, (dvoid *) 0, 
(dvoid * (*)(dvoid *,size_t)) 0, 
(dvoid * (*)(dvoid *, dvoid *, size_t)) 0, 
(void (*)(dvoid *, dvoid *)) 0, (size_t) 0, (dvoid **) 0))  
{ printf("FAILED: OCIEnvCreate()\n"); 
return OCI_ERROR;  
}  
/* allocate error handle */ 
if (OCIHandleAlloc( (dvoid *)envhp, (dvoid **) errhp,  
(ub4) OCI_HTYPE_ERROR, (size_t) 0, (dvoid **) 0)) 
{ printf("FAILED: OCIHandleAlloc() on errhp\n"); 
return OCI_ERROR;  
}  
/* allocate server handle */ 
if (status = OCIHandleAlloc( (dvoid*)envhp, (dvoid **) &srvhp,  
(ub4) OCI_HTYPE_SERVER, (size_t) 0, (dvoid **) 0)) 
{ printf("FAILED: OCIHandleAlloc() on srvhp\n"); 
checkerr( errhp, status); 
return OCI_ERROR;  
}  
/* allocate service context handle */ 
if (status = OCIHandleAlloc(( dvoid*)envhp, (dvoid **) &svchp,  
(ub4) OCI_HTYPE_SVCCTX, (size_t) 0, (dvoid **) 0)) 
{ printf("FAILED: OCIHandleAlloc() on svchp\n"); 
checkerr( errhp, status); 
return OCI_ERROR;  
}  
/* allocate session handle */ 
if (status = OCIHandleAlloc( (dvoid*)envhp, (dvoid **) &authp,  
(ub4) OCI_HTYPE_SESSION, (size_t) 0, (dvoid **) 0)) 
{ printf("FAILED: OCIHandleAlloc() on authp\n"); 
checkerr( errhp, status); 
return OCI_ERROR;  
}  

/* Allocate statement handle */ 
if (status = OCIHandleAlloc( (dvoid*)envhp, (dvoid **) stmthp,  
(ub4) OCI_HTYPE_STMT, (size_t) 0, (dvoid **) 0)) 
{ printf("FAILED: OCIHandleAlloc() on stmthp\n"); 
checkerr( errhp, status); 
return OCI_ERROR;  
}  
return OCI_SUCCESS; 
}