Now that you understand the mechanics of creating an OCI XML application, we can examine the Update application’s Main function:
#include "xmlupdate.h"
/*---------------------------Main function -----------------------------*/
int main(argc, argv)
int argc;
char *argv[];
{
/* OCI Handles and Variables */
OCIEnv *envhp = (OCIEnv *) 0;
OCIServer *srvhp = (OCIServer *) 0;
OCISvcCtx *svchp = (OCISvcCtx *) 0;
OCIError *errhp = (OCIError *) 0;
OCISession *authp = (OCISession *) 0;
OCIStmt *stmthp = (OCIStmt *) 0;
/* database login information */
text *user=(text *)"SH";
text *password=(text *)"SH";
/*Service Name for DB instance if remote DB */
text *conn=(text *)";
/* Miscellaneous */
boolean tab_exists = TRUE;
ub4 row = 1;
if (argc < 3) {
printf("\nUsage error: xmlupdate \"<SQL/XML Query>\" \"<XPath>\"
\"<value>\"\n\n");
return OCI_ERROR;
}
/* Initialize the environment and allocate handles */
if (init_env_handle(&envhp, &svchp, &errhp, &srvhp, &authp, &stmthp))
{
printf("FAILED: init_env_handle()!\n");
return OCI_ERROR;
}
/* Log on to the server and begin a session */
if (connect_server(srvhp, errhp, svchp, authp, user, password))
{
printf("FAILED: connect_server()!\n");
cleanup(envhp);
return OCI_ERROR;
}
/* Select an xmltype column by defining it to an xmltype instance,
apply some OCIXMLType and unified DOM APIs */
row = 1;
if (select_test_xml(envhp, svchp, errhp, stmthp, row, (text *)argv[1],
(text *)argv[2], (text *)argv[3]))
{
printf("FAILED: select_test_xml()!\n");
disconnect_server(envhp, svchp, errhp, authp, srvhp, stmthp, tab_exists);
return OCI_ERROR;
}
/* Detach from a server and clean up the environment */
disconnect_server(envhp, svchp, errhp, authp, srvhp, stmthp, tab_exists);
return OCI_SUCCESS;
}
Note that the application has the software steps of initialization; connecting to the database; submitting the query; performing the application logic on the results; and cleaning up before exiting. In the following sections, you will see the details of each of these steps as the application is built out.