mysql_ccode.c

在力LINUX下用C编写MYSQL的客户端程序,包括如何建立连接.如何创建表,删除表,以及更新记录等基本操作

#include <stdio.h>
#include <mysql.h>
/*#########const define###############*/
#define MY_HOST_NAME "localhost";
#define MY_USER_NAME "colefan";
#define MY_PWD "";
#define MY_DB_NAME "spider";
/*####################################*/
/*#########variable define#############*/
int mysql_connected=0;
MYSQL mysql_conn;
/*#####################################*/
/*########function define################*/
int my_db_connect();
void my_db_close();
int my_db_query();
int my_db_Init();
int GetNextSearchURL(char * currenturl);
/*######################################*/
int main(int argc,char * argv[]){
	MYSQL my;
	char cur[1024]="";
//	my_db_Init();
	if (GetNextSearchURL(cur)>0)
		printf("%s\n",cur);

//	my_db_query();
	my_db_close();	
	return 0;
	
}

/*#####open data base###*/
int my_db_connect(){
	int result=-1;
	if (mysql_connected!=0) return 1;
	
	if (mysql_init(&mysql_conn)!=NULL){
		if (mysql_real_connect(&mysql_conn,"localhost","colefan","","spider",MYSQL_PORT,NULL,0)!=NULL){
			mysql_connected=1;
		
			result=1;
		}
	}
	if (result!=1) mysql_connected=0;
	return result;
}
/*#####close data base####*/ 
void my_db_close(){
	if (mysql_connected==0) return;
	mysql_close(&mysql_conn);
	mysql_connected=0;
}
/*####query data base###*/
int my_db_query(){
	MYSQL_RES* mysql_result;
	int row_nums;
	long id=-1;
	MYSQL_ROW mysql_row;
	if(my_db_connect()>0){
		mysql_query(&mysql_conn,"select min(id) from tb_url where state=0;");
		mysql_result=mysql_store_result(&mysql_conn);
		row_nums=mysql_num_rows(mysql_result);
		printf("row_nums=%d\n",row_nums);
		if (row_nums>0){
			mysql_row=mysql_fetch_row(mysql_result);
			id=(long)mysql_row[0];
			printf("id=%s\n",mysql_row[0]);
			
		}
		mysql_free_result(mysql_result);
		return 1;
	}else{
		return 0;
	}
}
/*####Init Date base:create table,drop table####*/
int my_db_Init(){
	int result=-1;
	char sql[1024]="DROP TABLE IF EXISTS tb_url;";
	if(my_db_connect()>0){
		if(mysql_query(&mysql_conn,sql)==0){
			strcpy(sql,"CREATE TABLE IF NOT EXISTS tb_url(id BIGINT NOT NULL  AUTO_INCREMENT PRIMARY KEY,url varchar(255) NOT NULL UNIQUE,hashcode varchar(64),state int DEFAULT 0);");
			if(mysql_query(&mysql_conn,sql)==0){
				result=1;
			}
		}
	}

	return result;
		
}
/*********************************/
int GetNextSearchURL(char * currenturl){
	char sql[1024]="select min(id) from tb_url where state=0;";
	MYSQL_RES * mysql_result;
	MYSQL_ROW mysql_row;
	int bshouldDo=1;
	char id_string[1024]="";
	int rownums=-1;
	int result=-1;
	if (my_db_connect()>0){
		if(mysql_query(&mysql_conn,sql)==0){
			mysql_result=mysql_store_result(&mysql_conn);
			mysql_row=mysql_fetch_row(mysql_result);
			sprintf(id_string,"%s",mysql_row[0]);
			mysql_free_result(mysql_result);
			if (strstr(id_string,"null")!=NULL) bshouldDo=0;
			if(strstr(id_string,"NULL")!=NULL) bshouldDo=0;		
			
		}else return -1;

		if (bshouldDo){
			strcpy(sql,"select url from tb_url where id=");
			strcat(sql,id_string);
			strcat(sql,";");
			if(mysql_query(&mysql_conn,sql)==0){
				mysql_result=mysql_store_result(&mysql_conn);
				rownums=mysql_num_rows(mysql_result);
				if (rownums>0){
					mysql_row=mysql_fetch_row(mysql_result);
					strcpy(currenturl,mysql_row[0]);
					mysql_free_result(mysql_result);
					return 1;
				}else{
				 mysql_free_result(mysql_result);
				 return -1;
				}
			}else{
			return -1;
			}
		}
	}
	return result;
}