在Linux下通过C语言访问MySQL数据库的方法-mysql教程

错误提示：Can

错误提示：Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'

解决方法：在/var/run/ 下面创建一个 mysqld目录，然后建立一个链接指向：/opt/lampp/var/mysql/mysql.sock

输入指令： ln -s /opt/lampp/var/mysql/mysql.sock /var/run/mysqld/mysqld.sock

即可解决。

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main.c文件 程序代码如下：

//=======================================================================

#include
#include
#include

main()
{
char dbhost[32],dbuser[16],dbpasswd[16],dbname[16];
char query[256];
int count;
MYSQL * mysql; /*表示对一个数据库连接的句柄*/
MYSQL_RES *mysql_res; /*代表返回行的一个查询的结果*/
MYSQL_ROW mysql_row; /*字符串数组*/
MYSQL_FIELD *field;
my_ulonglong rows;
int i,num_fields;
/*该类型用于行编号和mysql_affected_rows()、mysql_num_rows()和mysql_insert_id()
* */

sprintf(dbhost,"localhost");
sprintf(dbuser,"root");
sprintf(dbpasswd,"123456");
sprintf(dbname,"system");

if(!(mysql=mysql_init(NULL))) /*获得或初始化一个MYSQL结构*/
{
printf("mysql_init失败!");
mysql_close(mysql);
exit(0);
}

if(!mysql_real_connect(mysql,dbhost,dbuser,dbpasswd,dbname,3306,NULL,0))
{ /*连接一个MySQL服务器*/
printf("%s",mysql_error(mysql));
printf("\n连接服务器失败,请联系系统管理人员!\n");
mysql_close(mysql);
exit(0);
}

strcpy(query,"select * from ns_materiel_import where status=0 order by itemid asc limit 1000");
if(mysql_query(mysql,query)) /*执行指定为一个空结尾的字符串的SQL查询*/
{
printf("%s",mysql_error(mysql));
printf("\nmysql_query出错!\n");
mysql_close(mysql);
exit(0);
}
mysql_res=mysql_store_result(mysql); /*检索一个完整的结果集合给客户*/
rows=mysql_num_rows(mysql_res); /*返回一个结果集合重的列的数量*/
if(rows==0) /*此管理码不存在 返回*/
{
printf("\n返回值为空\n");
mysql_free_result(mysql_res); /*释放一个结果集合使用的内存*/
mysql_close(mysql); /*关闭一个服务器连接*/
exit(0);
}
else
{
num_fields = mysql_num_fields(mysql_res);
for(i = 0; i {
field = mysql_fetch_field_direct(mysql_res, i);
printf("%s\t", field->name);
}


for(count=0; count {
mysql_row=mysql_fetch_row(mysql_res); /*从结果集合中取得下一行*/
for(i = 0; i {
printf("%s\t",mysql_row[i]);
}
printf("\n");
}

}

#if 0
for(count=0; count {
mysql_row=mysql_fetch_row(mysql_res); /*从结果集合中取得下一行*/
printf("用户ID:%s\t",mysql_row[0]);
printf("用户名:%s\t",mysql_row[2]);
printf("真实姓名:%s\t",mysql_row[4]);
printf("昵称:%s\t",mysql_row[5]);
printf("职务:%s\t",mysql_row[7]);
printf("电话:%s\n",mysql_row[8]);
}
#endif

mysql_free_result(mysql_res);
mysql_close(mysql);
printf("\nApp exit!!!\n");
}

*******************************************************************************************************************

Makefile 文件内容如下：

#=======================================================================
# Makefile template write by albert.shi
# 2011-06-03 21:09
# Shanghai
#=======================================================================

# Standard defines:
CC = gcc

WRES = windres

HOMEV = /usr/src/linux-2.6.32.21
VPATH = $(HOMEV)/include
oDir = .
Bin = .
Src = .
libDirs =
incDirs =

LIBS = -s -rdynamic -L/usr/lib/mysql -lmysqlclient
C_FLAGS += -I/usr/include/mysql/ -DBIG_JOINS=1 -fno-strict-aliasing -DUNIV_LINUX -DUNIV_LINUX -Wl,-Bsymbolic-functions

#C_FLAGS = -O -I/usr/include/mysql -DBIG_JOINS=1 -fno-strict-aliasing -DUNIV_LINUX -DUNIV_LINUX -Wl,-Bsymbolic-functions -rdynamic -L/usr/lib/mysql -lmysqlclient

SRCS =\
$(Src)/main.c\
# $(Src)/getfileargv.c\
# $(Src)/bdidll.c\
# $(Src)/bdisetup.c

EXOBJS =\
$(oDir)/main.o\
# $(oDir)/getfileargv.o\
#$(oDir)/bdidll.o\
#$(oDir)/bdisetup.o

ALLOBJS = $(EXOBJS)
ALLBIN = $(Bin)/app
ALLTGT = $(Bin)/app

# User defines:

#@# Targets follow ---------------------------------

all: $(ALLTGT)

objs: $(ALLOBJS)

cleanobjs:
rm -f $(ALLOBJS)

cleanbin:
rm -f $(ALLBIN)

cleantgt:
rm -f $(ALLTGT)

clean: cleanobjs cleanbin

cleanall: cleanobjs cleanbin cleantgt

#@# User Targets follow ---------------------------------

#@# Dependency rules follow -----------------------------
#--- list all bin file ----------------------------------
$(ALLTGT): $(EXOBJS)
$(CC) -o $(ALLBIN) $(EXOBJS) $(incDirs) $(libDirs) $(LIBS)

#--------------------------------------------------------
#---- compile all *.c to *.c ------
%.o : %.c
$(CC) $(C_FLAGS) $(incDirs) -c -o $@ $<

#--- another way to compile *.c to *.o------
#$(oDir)/main.o : main.c
# $(CC) $(C_FLAGS) $(incDirs) -c -o $@ $<

#--------------------------------------------------------