一个简单的mysql与C的交互，使用了一些mysql的C API！
老鸟掠过，新手能够看看！
/****************************************** 本文件学习mysql的database使用 学习mysql的C接口 包括初始化db，检查数据库是否存在，不存在就创建。 检查表是否存在，不存在则创建 *****************************************/#include#include #include //须要包括mysql的头文件，/usr/include/mysql///编译的时候须要加上-L/usr/lib/ -lmysqlclient -I/usr/include/mysql选项#include //主要的头文件，一些重要结构体的声明#include //错误信息的存放#include //包括当前mysql的版本号信息//所有变量，宏定义//#define DEBUG#define SERVER_HOST "localhost" //mysql的远程地址#define SERVER_USER "root" //数据库登录名#define SERVER_PWD "123" //数据库登录password#define DB_NAME "tmp_db" //新建数据库的名字#define TABLE_NAME "mytables" //库中的表int check_tbl(MYSQL* mysql,char *name);int check_db(MYSQL *mysql,char *db_name);int init_db(){ int err=0; MYSQL mysql; if(!mysql_init(&mysql)){ perror("mysql_init:"); exit(1); } if(!mysql_real_connect(&mysql,SERVER_HOST,SERVER_USER,SERVER_PWD,NULL,0,NULL,0)) { perror("mysql_real_connect"); exit(1); } printf("connected.....\n"); err = check_db(&mysql,DB_NAME); if(err != 0) { printf("create db is err!\n"); mysql_close(&mysql); exit(1); } //select which db if(mysql_select_db(&mysql,DB_NAME)) //return 0 is success ,!0 is err { perror("mysql_select_db:"); mysql_close(&mysql); exit(1); } //chuangjianbiao if((err=check_tbl(&mysql,TABLE_NAME))!=0) { printf("check_tbl is err!\n"); mysql_close(&mysql); exit(1); } mysql_close(&mysql); return 0;}int check_db(MYSQL *mysql,char *db_name){ MYSQL_ROW row = NULL; MYSQL_RES *res = NULL; res = mysql_list_dbs(mysql,NULL); if(res) { while((row = mysql_fetch_row(res))!=NULL) { printf("db is %s\n",row[0]); if(strcmp(row[0],db_name)==0) { printf("find db %s\n",db_name); break; } } //mysql_list_dbs会分配内存，须要使用mysql_free_result释放 mysql_free_result(res); } if(!row) //没有这个数据库，则建立 { char buf[128]={0}; strcpy(buf,"CREATE DATABASE "); strcat(buf,db_name);#ifdef DEBUG printf("%s\n",buf);#endif if(mysql_query(mysql,buf)){ fprintf(stderr,"Query failed (%s)\n",mysql_error(mysql)); exit(1); } } return 0;}int check_tbl(MYSQL* mysql,char *name){ if(name == NULL) return 0; MYSQL_ROW row=NULL; MYSQL_RES *res = NULL; res = mysql_list_tables(mysql,NULL); if(res) { while((row = mysql_fetch_row(res))!=NULL) { printf("tables is %s\n",row[0]); if(strcmp(row[0],name) == 0) { printf("find the table !\n"); break; } } mysql_free_result(res); } if(!row) //create table { char buf[128]={0}; char qbuf[128]={0}; snprintf(buf,sizeof(buf),"%s (name VARCHAR(20),sex char(1),score int(3));",TABLE_NAME); strcpy(qbuf,"CREATE TABLE "); strcat(qbuf,buf);//#ifdef DEBUG printf("%s\n",qbuf);//#endif if(mysql_query(mysql,qbuf)){ fprintf(stderr,"Query failed (%s)\n",mysql_error(mysql)); exit(1); } } return 0;}int main(){ int err=0; err = init_db(); return 0;}
编译的方法：最后的-I一定要注意检查这个文件夹是不是存在，否则会报错
gcc -o mysql mysql.c -L/usr/lib/ -lmysqlclient -I/usr/include/mysql
报错：
root@jack-desktop:~# gcc -o mysql mysql.c -L/usr/lib/ -lmysqlclientgcc: mysql.c: 没有那个文件或文件夹root@jack-desktop:~# root@jack-desktop:~# root@jack-desktop:~# cd myc/root@jack-desktop:myc# gcc -o mysql mysql.c -L/usr/lib/ -lmysqlclientmysql.c:15:73: error: mysql.h: 没有那个文件或文件夹mysql.c:16:43: error: errmsg.h: 没有那个文件或文件夹mysql.c:17:63: error: mysql_version.h: 没有那个文件或文件夹mysql.c:27: error: expected ‘)’ before ‘*’ tokenmysql.c:28: error: expected ‘)’ before ‘*’ tokenmysql.c: In function ‘init_db’:mysql.c:34: error: ‘MYSQL’ undeclared (first use in this function)mysql.c:34: error: (Each undeclared identifier is reported only oncemysql.c:34: error: for each function it appears in.)mysql.c:34: error: expected ‘;’ before ‘mysql’mysql.c:36: error: ‘mysql’ undeclared (first use in this function)mysql.c: At top level:mysql.c:73: error: expected ‘)’ before ‘*’ tokenmysql.c:109: error: expected ‘)’ before ‘*’ token