How to Know records updated with Update query? - mysql

Question

How to know whether any record in the table updated with the update query or not.
I am using the Mysql C API..i have tried storing the mysql result after firing the UPDATE query but result is always returning NULL for successful upation also. Any help would be great.
Thanks
int main(void)
{
MYSQL *conn;
MYSQL_RES *res;
MYSQL_ROW row;
if ((conn = mysql_init(NULL)) == NULL)
{
fprintf(stderr, "Could not init DB\n");
return EXIT_FAILURE;
}
if (mysql_real_connect(conn, "localhost", "root", "password", "cpaas", 0, NULL, 0) == NULL)
{
fprintf(stderr, "DB Connection Error\n");
return EXIT_FAILURE;
}
if (mysql_query(conn, "update calldirection set callid='Hello' where callid='He'") != 0)
{
fprintf(stderr, "Query Failure\n");
return EXIT_FAILURE;
}
res = mysql_store_result(conn);
if(res == NULL){
printf("dssdg");
return 1;
}
if ((row = mysql_num_rows(res)) <= 0)
{
printf("FFFFFFF");
}
mysql_close(conn);
return EXIT_SUCCESS;
}

Answer 1

After Doing Some R&D nearly for 1 day...I found mysql_affected_rows(*mysql) function which will return the number of rows updated for the UPDATE query.

Answer 2

As stated in MySQL mysql-store-resul
After invoking mysql_query() or mysql_real_query(), you must call
mysql_store_result() or mysql_use_result() for every statement that
successfully produces a result set (SELECT, SHOW, DESCRIBE, EXPLAIN,
CHECK TABLE, and so forth). You must also call mysql_free_result()
after you are done with the result set.
You need not call mysql_store_result() or mysql_use_result() for other
statements, but it does not do any harm or cause any notable
performance degradation if you call mysql_store_result() in all cases.
You can detect whether the statement has a result set by checking
whether mysql_store_result() returns a nonzero value (more about this
later)
mysql_store_result returns NULL for the queries other than (SELECT, SHOW, DESCRIBE, EXPLAIN, CHECK TABLE) query types.
and Update query is not one of them, thus mysql_store_result returns NULL for it.