C Database Programming Video Tutorial124

Introduction

C is a powerful programming language that is widely used for developing high-performance and efficient applications. It is also a popular choice for database programming, as it provides a number of features that make it well-suited for this task. In this video tutorial, we will learn the basics of C database programming, including how to connect to a database, execute queries, and retrieve data.

Prerequisites

Before you can start this tutorial, you need to have a basic understanding of C programming. You should also have a working knowledge of SQL (Structured Query Language), which is the standard language used to interact with databases.

Getting Started

To start, you need to include the necessary header files for database programming in your C program. The most important header file is , which provides functions for input and output. You also need to include the header file, which provides functions for memory management.
#include <stdio.h>
#include <stdlib.h>

Next, you need to establish a connection to the database. To do this, you use the mysql_init() function to create a new MySQL connection object. You then use the mysql_real_connect() function to connect to the database, specifying the hostname, username, password, database name, and port number.
MYSQL *conn;
conn = mysql_init(NULL);
if (!mysql_real_connect(conn, "localhost", "root", "password", "test", 3306, NULL, 0)) {
fprintf(stderr, "%s", mysql_error(conn));
mysql_close(conn);
exit(1);
}

Once you have a connection to the database, you can start executing queries. To do this, you use the mysql_query() function. The mysql_query() function takes a query string as its argument and executes the query on the database. If the query is successful, the mysql_query() function returns 0. Otherwise, it returns a non-zero value.
char *query = "SELECT * FROM users";
if (mysql_query(conn, query)) {
fprintf(stderr, "%s", mysql_error(conn));
mysql_close(conn);
exit(1);
}

After you have executed a query, you can retrieve the results using the mysql_store_result() function. The mysql_store_result() function returns a MYSQL_RES object, which contains the results of the query.
MYSQL_RES *res;
res = mysql_store_result(conn);
if (!res) {
fprintf(stderr, "%s", mysql_error(conn));
mysql_close(conn);
exit(1);
}

You can then use the mysql_fetch_row() function to iterate over the results of the query. The mysql_fetch_row() function returns a pointer to an array of strings, where each string contains a value from the current row of the query results.
MYSQL_ROW row;
while ((row = mysql_fetch_row(res))) {
printf("%s", row[0]);
}

Finally, you need to close the connection to the database when you are finished. To do this, you use the mysql_close() function.
mysql_close(conn);

Example Program

The following program demonstrates how to use C to connect to a database, execute a query, and retrieve the results:
#include <stdio.h>
#include <stdlib.h>
#include <mysql/mysql.h>
int main() {
MYSQL *conn;
MYSQL_RES *res;
MYSQL_ROW row;
char *query = "SELECT * FROM users";
conn = mysql_init(NULL);
if (!mysql_real_connect(conn, "localhost", "root", "password", "test", 3306, NULL, 0)) {
fprintf(stderr, "%s", mysql_error(conn));
mysql_close(conn);
exit(1);
}
if (mysql_query(conn, query)) {
fprintf(stderr, "%s", mysql_error(conn));
mysql_close(conn);
exit(1);
}
res = mysql_store_result(conn);
if (!res) {
fprintf(stderr, "%s", mysql_error(conn));
mysql_close(conn);
exit(1);
}
while ((row = mysql_fetch_row(res))) {
printf("%s", row[0]);
}
mysql_close(conn);
return 0;
}

Conclusion

In this video tutorial, we have learned the basics of C database programming. We have seen how to connect to a database, execute queries, and retrieve data. With this knowledge, you can start developing your own database applications in C.

2024-11-27

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