code-odbc-connect-to-database.md
// Demonstrate connecting to Vertica using ODBC.
// Standard i/o library
#include <stdio.h>
#include <stdlib.h>
// Only needed for Windows clients
// #include <windows.h>
// SQL include files that define data types and ODBC API
// functions
#include <sql.h>
#include <sqlext.h>
#include <sqltypes.h>
int main()
{
SQLRETURN ret; // Stores return value from ODBC API calls
SQLHENV hdlEnv; // Handle for the SQL environment object
// Allocate an a SQL environment object
ret = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hdlEnv);
if(!SQL_SUCCEEDED(ret)) {
printf("Could not allocate a handle.\n");
exit(EXIT_FAILURE);
} else {
printf("Allocated an environment handle.\n");
}
// Set the ODBC version we are going to use to
// 3.
ret = SQLSetEnvAttr(hdlEnv, SQL_ATTR_ODBC_VERSION,
(SQLPOINTER) SQL_OV_ODBC3, SQL_IS_UINTEGER);
if(!SQL_SUCCEEDED(ret)) {
printf("Could not set application version to ODBC 3.\n");
exit(EXIT_FAILURE);
} else {
printf("Set application version to ODBC 3.\n");
}
// Allocate a database handle.
SQLHDBC hdlDbc;
ret = SQLAllocHandle(SQL_HANDLE_DBC, hdlEnv, &hdlDbc);
if(!SQL_SUCCEEDED(ret)) {
printf("Could not allocate database handle.\n");
exit(EXIT_FAILURE);
} else {
printf("Allocated Database handle.\n");
}
// Connect to the database using
// SQL Connect
printf("Connecting to database.\n");
const char *dsnName = "ExampleDB";
const char* userID = "ExampleUser";
const char* passwd = "password123";
ret = SQLConnect(hdlDbc, (SQLCHAR*)dsnName,
SQL_NTS,(SQLCHAR*)userID,SQL_NTS,
(SQLCHAR*)passwd, SQL_NTS);
if(!SQL_SUCCEEDED(ret)) {
printf("Could not connect to database.\n");
exit(EXIT_FAILURE);
} else {
printf("Connected to database.\n");
}
// We're connected. You can do real
// work here
// When done, free all of the handles to close them
// in an orderly fashion.
printf("Disconnecting and freeing handles.\n");
ret = SQLDisconnect( hdlDbc );
if(!SQL_SUCCEEDED(ret)) {
printf("Error disconnecting from database. Transaction still open?\n");
exit(EXIT_FAILURE);
}
SQLFreeHandle(SQL_HANDLE_DBC, hdlDbc);
SQLFreeHandle(SQL_HANDLE_ENV, hdlEnv);
exit(EXIT_SUCCESS);
}