1、数据库的增删改

#include <myhead.h>
int main(int argc, const char *argv[])
{//定义数据库句柄指针sqlite3 *kdb=NULL;//打开数据库，不存在则创建if(sqlite3_open("./my.db",&kdb)!=SQLITE_OK){printf("sqlite3_open error\n");return -1;}printf("sqlite3_open success\n");//创建数据表//准备sql语句char sql[128]="create table if not exists worker(id double,name char,salary double)";	char *errmsg=NULL;//存放执行sql语句的错误信息if(sqlite3_exec(kdb,sql,NULL,NULL,&errmsg)!=SQLITE_OK){printf("exec error:%s\n",errmsg);sqlite3_free(errmsg);//防止内存泄露errmsg=NULL;return -1;}//增删改查int key=-1;while(1){printf("\t\t\t＝＝信息表＝＝\n");printf("\t\t1、插入信息\n");printf("\t\t2、删除信息\n");printf("\t\t3、修改信息\n");printf("\t\t4、退出\n");scanf("%d",&key);int id=0;;char name[10]="";int salary=0;;switch(key){case 1:{printf("please enter id:");scanf("%d",&id);printf("please enter name:");scanf("%s",name);printf("please enter salary:");scanf("%d",&salary);char sq1[128]="";sprintf(sq1,"insert into worker(id,name,salary) values(%d,'%s',%d)",id,name,salary);if(sqlite3_exec(kdb,sq1,NULL,NULL,&errmsg)!=SQLITE_OK){printf("add error\n");sqlite3_free(errmsg);//防止内存泄露errmsg=NULL;return -1;}printf("add success\n");}break;case 2:{printf("please enter id to delete:");scanf("%d",&id);char sq2[128]="";sprintf(sq2,"delete from worker where id=%d",id);if(sqlite3_exec(kdb,sq2,NULL,NULL,&errmsg)!=SQLITE_OK){printf("delete error\n");sqlite3_free(errmsg);//防止内存泄露errmsg=NULL;return -1;}printf("delete success\n");}break;case 3:{int n=-1;printf("please enter 1 to modify id,2 to modify name,3 to modify salary\n");scanf("%d",&n);if(n==1){int oldid=0;printf("please enter old id:");scanf("%d",&oldid);printf("please enter new id:");scanf("%d",&id);char sq3[128]="";sprintf(sq3,"update worker set id=%d where id=%d",id,oldid);if(sqlite3_exec(kdb,sq3,NULL,NULL,&errmsg)!=SQLITE_OK){printf("modify error\n");sqlite3_free(errmsg);//防止内存泄露errmsg=NULL;return -1;}printf("modify success\n");}if(n==2){printf("please enter id:");scanf("%d",&id);printf("please enter new name:");scanf("%s",name);char sq4[128]="";sprintf(sq4,"update worker set name='%s' where id=%d",name,id);if(sqlite3_exec(kdb,sq4,NULL,NULL,&errmsg)!=SQLITE_OK){printf("modify error\n");sqlite3_free(errmsg);//防止内存泄露errmsg=NULL;return -1;}printf("modify success\n");}if(n==3){printf("please enter id:");scanf("%d",&id);printf("please enter new salary:");scanf("%d",&salary);char sq5[128]="";sprintf(sq5,"update worker set salary=%d where id=%d",salary,id);if(sqlite3_exec(kdb,sq5,NULL,NULL,&errmsg)!=SQLITE_OK){printf("modify error\n");sqlite3_free(errmsg);//防止内存泄露errmsg=NULL;return -1;}printf("modify success\n");}}break;}if(key==4){printf("退出成功\n");break;}}//关闭数据库sqlite3_close(kdb);return 0;
}

 

2、思维导图