//1.创建数据库

    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject]stringByAppendingPathComponent:@"student"];

    FMDatabase *dataBase = [FMDatabase databaseWithPath:path];

    self.dataBase = dataBase;

    

    BOOL success = [dataBase open];

    if (success) {

        NSLog(@"数据库创建成功!");

        //2.创建表

        NSString *str = @"CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, score REAL NOT NULL)";

        if ([self.dataBase executeUpdate:str]) {

            NSLog(@"表创建成功!");

        }else{

            NSLog(@"创建表失败!");

        }

    }else{

        NSLog(@"数据库创建失败!");

    }

 

    //3.增加 数据 (100条 数据随机)

    for (int i = 0; i <100; i++) {

        

        NSString *strName = [NSString stringWithFormat:@"8mingyeuxin-%d",i];

        

        NSString *sqlStr = [NSString stringWithFormat:@"INSERT INTO t_student (name ,score)VALUES('%@',%.02f)",strName,arc4random_uniform(1000)/10.0];

        

        //执行 //非查询语句  执行的方法

        BOOL success =  [self.dataBase executeUpdate:sqlStr];

        if (success) {

            NSLog(@"添加成功!");

        }else{

            NSLog(@"添加失败!");

        }

        

    }

    

NSString *strSql =  @"SELECT * FROM t_student WHERE score > 60.0 ORDER BY score DESC;";

    //查询语句  执行的方法

    FMResultSet *set =  [self.dataBase executeQuery:strSql];

    while ([set next]) {

        //name

        //NSString *name = [set stringForColumnIndex:1];

         NSString *name = [set stringForColumn:@"name"];

        //score

        CGFloat score = [set doubleForColumn:@"score"];

        

        NSLog(@"name = %@  score = %f",name,score);

    }