After MySQL is installed, an include directory and a lib directory are generated under mysql. The include directory holds the header file, and the lib is the dynamic link library. Copy mysql.h under include / to / usr/include, and copy libmysqlclient.so and libmysqlclient.so.18 under lib / to / usr/lib64. The writing program needs to include the mysql.h header file. Add - lmysqlclient when linking

The source code is connect.c, where all the header files are placed under the /usr/include/mysql file. The principle is very simple. First initialize a handle, then call the connection function and pass in the username and password. Here, connect to the database named "wz" and "wz", and query all the data as follows:

#include <stdio.h>
#include <mysql/mysql.h>
#include <string.h>

void main()
{
    MYSQL mysql;
    MYSQL_RES *res = NULL;
    MYSQL_ROW row;
    char *query_str = NULL;
    int rc, i, fields;
    int rows;

    /* Initialization handle */
    if (NULL == mysql_init(&mysql))
    {
        printf("mysql_init() : %s\n", mysql_error(&mysql));
        return;
    }

    /* Establish connection with database */
    if (NULL == mysql_real_connect(&mysql, "localhost", "root",
                    "123456", "wz", 0, NULL, 0))
    {
        printf("mysql_real_connect() : %s\n", mysql_error(&mysql));
        return;
    }
    printf("connect mysql successful\n");

    /* Set character set to uft8 to support Chinese */
    if (mysql_set_character_set(&mysql, "utf8"))
    {
	    printf("mysql_set_character_set(): %s\n", mysql_error(&mysql));
	    return;
    }

    /* Set query statement */
    query_str = "select * from wz";
    rc = mysql_real_query(&mysql, query_str, strlen(query_str));
    if (rc != 0)
    {
	    printf("mysql_real_query() : %s\n", mysql_error(&mysql));
	    return;
    }

    /* Reception result */
    res = mysql_store_result(&mysql);
    if (NULL == res)
    {
        printf("mysql_store_result(): %s\n", error(&mysql));
        return;
    }

    /* Get rows and columns */
    rows = mysql_num_rows(res);
    printf("The total rows is: %d\n", rows);
    fields = mysql_num_fields(res);
    printf("The total fields is: %d\n", fields);

    /* Print all attributes in circular row and column */
    while ((row = mysql_fetch_row(res)))
    {
        for (i = 0; i < fields; i++)
        {
    	    printf("%s\n", row[i]);
        }
        printf("\n");
    }

    /* Disconnect */
    mysql_close(&mysql);
}

The implementation effect is as follows:

[root@1dot1dot1dot1 mysql]# ./start.sh 
connect mysql successful
The total rows is: 3
The total fields is: 4
1
//Study
edward
2018-09-13

9
//work
edward
2018-09-14

12
//entertainment
james
2018-09-14

Directly use the command line to query the results as follows:

mysql> select * from wz;
+----+--------+--------+------------+
| id | title  | author | date       |
+----+--------+--------+------------+
|  1 | Study   | edward | 2018-09-13 |
|  9 | work   | edward | 2018-09-14 |
| 12 | entertainment   | james  | 2018-09-14 |
+----+--------+--------+------------+
3 rows in set (0.02 sec)

Operations such as adding and deleting are similar. Just call the corresponding api