C 扩展库 - mysql API CRUD
2024-09-23 06:00:47
CRUD
table
create table if not exists `student` (
`id` int auto_increment,
`name` varchar(16) not null,
`age` int not null,
`address` varchar(128) not null,
primary key (`id`)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
code
//
// Created by zhangrongxiang on 2018/3/5 14:56
// File main
//
#include <mysql/mysql.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main() {
MYSQL *mysql = NULL;
// const char *host = "debian";
const char *host = "localhost";
const char *user = "root";
const char *passwd = "root";
const char *db = "fgap_config";
unsigned int port = 3306;
const char *unix_socket = "/var/run/mysqld/mysqld.sock";
int flag = 0, i = 0;
const char *db2 = "test";
char sql[1024] = {0};
if (mysql_library_init(0, NULL, NULL)) {
fprintf(stderr, "could not initialize MySQL client library\n");
exit(EXIT_FAILURE);
}
mysql = mysql_init(mysql);
if (mysql == NULL) {
perror("mysql_init error");
return EXIT_FAILURE;
}
printf("mysql_init success\n");
mysql = mysql_real_connect(mysql, host, user, passwd, db, port, unix_socket, 0);
if (mysql == NULL) {
fprintf(stderr, "Failed to connect to database: Error: %s\n", mysql_error(mysql));
return EXIT_FAILURE;
}
printf("mysql_real_connect success\n");
int ping = mysql_ping(mysql);
if (ping == 0) {
printf("mysql is active !\n");
} else {
return EXIT_FAILURE;
}
//////////////////////////////////////////////////////////////////
const char *clientInfo = mysql_get_client_info();
//5.5.58
printf("mysql_get_client_info : %s\n", clientInfo);
unsigned long version = mysql_get_client_version();
//50558 = 5*10000 + 5*100 + 58
//major_version*10000 + release_level*100 + sub_version
printf("mysql_get_client_version : %ld\n", version);
const char *serverInfo = mysql_get_server_info(mysql);
//5.5.58-0+deb8u1
printf("mysql_get_server_info : %s\n", serverInfo);
const char *hostInfo = mysql_get_host_info(mysql);
//Localhost via UNIX socket
printf("mysql_get_host_info : %s\n", hostInfo);
unsigned int protoInfo = mysql_get_proto_info(mysql);
//10
printf("mysql_get_proto_info : %d\n", protoInfo);
unsigned long serverVersion = mysql_get_server_version(mysql);
//50558
printf("mysql_get_server_version : %ld\n", serverVersion);
const char *mysqlInfo = mysql_info(mysql);
//(null)
printf("mysql_info : %s\n", mysqlInfo);
const char *stat = mysql_stat(mysql);
//mysql_stat : Uptime: 70217 Threads: 2 Questions: 824 Slow queries: 0 Opens: 69 Flush tables: 1 Open tables: 59 Queries per second avg: 0.011
printf("mysql_stat : %s\n", stat);
//////////////////////////////////////////////////////////////////
MYSQL_RES *pRes = mysql_list_dbs(mysql, NULL);
MYSQL_ROW row = NULL;
if (pRes) {
unsigned int fields = mysql_num_fields(pRes);
my_ulonglong rows = mysql_num_rows(pRes);
unsigned int count = mysql_field_count(mysql);
printf("mysql_num_fields : %d\n", fields);//1
printf("mysql_num_rows : %ld\n", (long) rows);//4
printf("mysql_field_count : %d\n", count);//1
while ((row = mysql_fetch_row(pRes)) != NULL) { // 打印结果集
// database: information_schema
// database: fgap_config
// database: mysql
// database: performance_schema
if (strcmp(row[fields - 1], db2) == 0) {
flag = 1;
}
printf("database: %-10s\n", row[fields - 1]);
}
mysql_free_result(pRes);
}
if (flag == 0) {
printf("no %s db -> %d\n", db2, flag);
//int mysql_create_db(MYSQL *mysql, const char *db)
/*
* //main.c:(.text+0x34f): undefined reference to `mysql_create_db'
if(mysql_create_db(mysql,"test") == 0){
printf("create test success\n");
} else{
printf("create test error\n");
}
*/
}
if (mysql_select_db(mysql, db2) == 0) {
printf("mysql_select_db(mysql, %s) success \n", db2);
MYSQL_RES *tables = mysql_list_tables(mysql, NULL);
unsigned int fields = mysql_num_fields(tables);
my_ulonglong rows = mysql_num_rows(tables);
printf("mysql_num_fields : %d\n", fields);//1
printf("mysql_num_rows : %d\n", (int) rows);//1
if (tables) {
flag = 0;
MYSQL_ROW fetchRow = NULL;
while ((fetchRow = mysql_fetch_row(tables)) != NULL) {
if (strcmp(fetchRow[fields - 1], "student") == 0)
flag = 1;
printf("table : %-10s\n", fetchRow[fields - 1]);
}
if (!flag) {
FILE *file = NULL;
file = fopen("student.sql", "r");
if (file) {
while (!feof(file)) {
char str[64] = {0};
fgets(str, sizeof(str), file);
strcat(sql, str);
}
printf("%s\n", sql);
} else {
fprintf(stderr, "fopen student.sql error\n");
exit(EXIT_FAILURE);
}
fclose(file);
int r = mysql_real_query(mysql, sql, (unsigned long) strlen(sql));
if (r == 0) {
printf("table student was created success !! \n");
} else {
printf("table student was created error !! \n");
exit(EXIT_FAILURE);
}
} else {
printf("table student already exists !! \n");
}
} else {
printf("something wrong\n");
}
}
/////////////////////////////////////////////////////////////////
memset(sql, 0, sizeof(sql));
sprintf(sql, "select count(id) from student");
int count = 0;
if (mysql_real_query(mysql, sql, (unsigned int) strlen(sql)) == 0) {
MYSQL_RES *result = mysql_store_result(mysql);
// my_ulonglong rows = mysql_num_rows(result);
unsigned int fields = mysql_num_fields(result);
MYSQL_ROW fetchRow = mysql_fetch_row(result);
count = atoi(fetchRow[fields - 1]);
printf("count %d\n", count);
mysql_free_result(result);
}
if (count < 50) {
memset(sql, 0, sizeof(sql));
for (i = 0; i < 10; ++i) {
char name[16] = {0};
char address[64] = {0};
sprintf(name, "zing-%d", i);
sprintf(address, "jiangsu-wuxi-%d", i);
sprintf(sql, "INSERT INTO `student` (`name`,`age`,`address`) VALUES('%s','%d','%s')", name, 10 + i,
address);
if (mysql_real_query(mysql, sql, (unsigned int) strlen(sql)) == 0) {
my_ulonglong id = mysql_insert_id(mysql);
printf("insert num %ld success\n", (long int) id);
}
}
}
memset(sql, 0, sizeof(sql));
sprintf(sql, "select * from student order by id asc limit 0,20");
if (mysql_real_query(mysql, sql, (unsigned int) strlen(sql)) == 0) {
MYSQL_RES *result = mysql_store_result(mysql);
unsigned int fields = mysql_num_fields(result);
printf("fields %d\n", fields);
MYSQL_ROW fetchRow;
while ((fetchRow = mysql_fetch_row(result)) != NULL) {
printf("id:%s name:%s age:%s address:%s \n", fetchRow[0], fetchRow[1], fetchRow[2], fetchRow[3]);
}
mysql_free_result(result);
}
///////////////////////////////////////////////////////////////////////////////////////
memset(sql, 0, sizeof(sql));
sprintf(sql, "update student set name='%s',age=%d,address='%s' where id between %d and %d;", "zhangrongxiang", 24,
"jiangsu-xuzhou-1", 1, 10);
if (mysql_real_query(mysql, sql, (int) strlen(sql)) == 0) {
printf("mysql_affected_rows : %d\n", (int) mysql_affected_rows(mysql));
}
mysql_close(mysql);
mysql_library_end();
return EXIT_SUCCESS;
}
/*
*
* Initialize the MySQL client library by calling mysql_library_init().
* This function exists in both the libmysqlclient C client library and the libmysqld embedded server library,
* so it is used whether you build a regular client program by linking with the -libmysqlclient flag, or an embedded server application by linking with the -libmysqld flag.
*
* Initialize a connection handler by calling mysql_init() and connect to the server by calling mysql_real_connect().
*
* Issue SQL statements and process their results. (The following discussion provides more information about how to do this.)
*
* Close the connection to the MySQL server by calling mysql_close().
*
* End use of the MySQL client library by calling mysql_library_end().
*/
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