Storing mysql database query as a variable in C - mysql

Question

I'm very new to C, and have been trying to fetch a result from mysql and store it as a variable to be called later. So far I've managed to connect to my database, fetch the result and print it to the terminal. But I have no idea how to now store it as a variable. Any help is greatly appreciated.
Here is what I have so far:
#include <mysql.h>
#include <stdio.h>
main() {
MYSQL *conn;
MYSQL_RES *res;
MYSQL_ROW row;
char *server = "localhost";
char *user = "root";
char *password = ""; /* set me first */
char *database = "develop";
conn = mysql_init(NULL);
/* Connect to database */
if (!mysql_real_connect(conn, server,
user, password, database, 0, NULL, 0)) {
fprintf(stderr, "%s\n", mysql_error(conn));
exit(1);
}
/* send SQL query */
if (mysql_query(conn, "SELECT * FROM action ")) {
fprintf(stderr, "%s\n", mysql_error(conn));
exit(1);
}
res = mysql_use_result(conn);
/* output table name */
printf("MySQL Data:\n");
while ((row = mysql_fetch_row(res)) != NULL)
printf("%s \n", row[0]);
/* close connection */
mysql_free_result(res);
mysql_close(conn);
}
Thanks,
Liam.

Answer 1

The same way you would store any variable in C. You've got the hard part down since you can output your information to the console. To store the variable, assign it. In C you declare the type, name, then your SQL statement. e.g.
#include <sys/time.h>
#include <stdio.h>
#include <mysql.h>
int main(char **args) {
MYSQL_RES *result;
MYSQL_ROW row;
MYSQL *connection, mysql;
int state;
Above is where the variables are declared. The part that says *result; is the PHP equivalent of $result
Below he's connecting to the database.
/* connect to the mySQL database at athens.imaginary.com */
mysql_init(&mysql);
connection = mysql_real_connect(&mysql,
"athens.imaginary.com",
0, 0,
"db_test", 0, 0);
/* check for a connection error */
if( connection == NULL ) {
/* print the error message */
printf(mysql_error(&mysql));
return 1;
}
state = mysql_query(connection,
"SELECT test_id, test_val FROM test");
if( state != 0 ) {
printf(mysql_error(connection));
return 1;
}
/* must call mysql_store_result() before we can issue any
* other query calls
*/
Assign the result, print the array
result = mysql_store_result(connection);
printf("Rows: %d\n", mysql_num_rows(result));
/* process each row in the result set */
while( ( row = mysql_fetch_row(result)) != NULL ) {
printf("id: %s, val: %s\n",
(row[0] ? row[0] : "NULL"),
(row[1] ? row[1] : "NULL"));
}
/* free the result set */
mysql_free_result(result);
/* close the connection */
mysql_close(connection);
Close the connection PHP speak: $conn = null;
printf("Done.\n");
}
Added notes to this source: http://docstore.mik.ua/orelly/linux/sql/ch13_01.htm