Chapter 3. Connecting to the Database

In order to interact with the database, you must first open a connection handle to the database server. The handle to the database is called MYSQL and is the structure you must use for subsequent calls to the database. Here is a sample snippet of code to connect to the database.

#include "mysql.h"
#include <stdio.h>
#include <stdlib.h>

MYSQL mysql;

void exiterr(int exitcode)
{
	fprintf( stderr, "%s\n", mysql_error(&mysql) );
	exit( exitcode );
}

int main()
{
	if (!(mysql_connect(&mysql,"host","username","password"))) 
		exiterr(1);

	if (mysql_select_db(&mysql,"payroll"))
		exiterr(2);

	/*...*/
}

The second call, mysql_select_db allows you to define which database you are using. You must call this before you continue to interact with the database.

For the connect call, you may specify any argument as NULL. If you specify the host as NULL, the localhost is assumed. If the user is NULL, then the current user is assumed. If password is NULL, then only users in the user table without a password entry will be checked for a match.

The error call mysql_error returns a string which explains the last error that occurred. More about MySQL errors will be discussed later.

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