#import <sqlite3.h>

@interface ViewController ()
{
 sqlite3 *_sqldb;
}

@end

@implementation ViewController

- (void)viewDidLoad
{
 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.
 [self OpenDb];
 [self createTable];
 [self insertData];
 [self FindData];
}


//打开数据库

-(void)OpenDb{
 
 NSArray *arrs= NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 //创建数据库，如果数据库存在就直接打开，不存在就创建打开
 NSString *path=[arrs lastObject] ;
 NSString *documentpath= [path stringByAppendingPathComponent:@"sql.db"];
 int reslut= sqlite3_open([documentpath UTF8String], &_sqldb);
 if(reslut==SQLITE_OK){
 NSLog(@"数据库已被打开");
 }
 
}
//通过数据库实例创建表
-(void)createTable{
 //不带参数的sql语句
 const char* sql="create table if not exists t_person (id integer primary key autoincrement,name text,age integer);";
 char *error;
 //sqlite3_exec可以执行一切不带参数的SQL语句。如果是带参数最好不用，防止SQL注入漏洞攻击
 int resutl= sqlite3_exec(_sqldb, sql, NULL, NULL, &error);
 if(resutl==SQLITE_OK){
 NSLog(@"创建表成功");
 }
else{
 NSLog(@"创建表失败－－》%s",error);
}
}

//插入数据
-(void)insertData{
 //带参数的SQL语句 "?"是带参数的占位符
 const char * sql="insert into t_person(name,age) values(?,?);";
 sqlite3_stmt *stmp;
 //在执行SQL语句之前检查SQL语句语法,-1代表字符串的长度
 int result= sqlite3_prepare_v2(_sqldb, sql, -1, &stmp, NULL);
 if(result==SQLITE_OK){
 NSLog(@"插入SQL语句语法没有问题");
 //绑定参数,插入的参数的下标是从1开始
 sqlite3_bind_text(stmp, 1, "gcb", -1, NULL);
 sqlite3_bind_int(stmp, 2, 12);
 
 //执行参参数的SQL语句，不能有exec
 int result=sqlite3_step(stmp);
 //插入进行判断,要用sqLite_Done来判断
 if(result==SQLITE_DONE){
  NSLog(@"插入成功");
 }
 else{
  NSLog(@"插入失败") ;
 }
 
 }
 else{
 NSLog(@"插入SQL语句有问题");
 }
}

-(void)FindData{
 char *sql="select id,name,age from t_person";
 //查询做好用step执行
 sqlite3_stmt *stmt;
 //检查SQL语句的语法问题
 int result= sqlite3_prepare_v2(_sqldb, sql, -1, &stmt, NULL);
 if(result==SQLITE_OK){
 while (sqlite3_step(stmt)==SQLITE_ROW) {
  //查询的列是0开始 插入的列从1开始
//  int xh＝sqlite3_column_int(stmt, 0);
  int xh=sqlite3_column_int(stmt, 0);
  char * name=(char *)sqlite3_column_text(stmt, 1);
  int age=sqlite3_column_int(stmt, 2);
  NSLog(@"xh=%i-->name=%s-->age=%i",xh,name,age);
  
  
  
 }
 }
 else{
 NSLog(@"查询SQL语法有误");
 }

}