Ios 数据库执行查询错误：SQL逻辑错误或缺少数据库xcode

我正在运行本教程中的代码。查询函数为：

- (IBAction)saveInfo:(id)sender
{
    //  Prepare the query string.
    //  If the recordIDToEdit property has value other than -1, then create an update query. Otherwise create an insert query.
    NSString *query;

    if (self.recordIDToEdit == -1)
    {
        query = [NSString stringWithFormat:@"insert into peopleInfo values(null, '%@', '%@', '%@')", self.txtFirstname.text, self.txtLastname.text, self.txtAge.text ];
    }
    else
    {
        query = [NSString stringWithFormat:@"update peopleInfo set firstname='%@', lastname='%@', age='%@' where peopleInfoID=%d", self.txtFirstname.text, self.txtLastname.text, self.txtAge.text, self.recordIDToEdit];
    }



    NSLog(@"The query is: %@",query);

    //  Execute the query.
    [self.dbManager executeQuery:query];

    //  If the query was succesfully executed then pop the view controller.
    if (self.dbManager.affectedRows != 0) {
        NSLog(@"Query was executed successfully. Affacted rows = %d", self.dbManager.affectedRows);

        //  Inform the delegate that editing was finished.
        [self.delegate editingInfoWasFinished];

        //  Pop the view controller.
        [self.navigationController popViewControllerAnimated:YES];
    }
    else
    {
        NSLog(@"Could not execute the query");
    }
}

程序在插入记录时出现sql错误

The query is: insert into peopleInfo values(null, 'Project 1', 'Test 1', '2014-12-15 05:00:20 +0000')
DB Execute Query Error: SQL logic error or missing database
Could not execute the query.

如何获取和删除此错误？

---

请参见突出显示的文件夹。将其复制到您的项目中。您的代码似乎很好。并确保db.sql在其中。

插入查询中的null是什么意思。该列是标识还是仅为整数？检查该列是否不为空。是否使用更新查询？是否已将数据库文件文件夹（与您引用的代码一起提供）导入到项目中？你可能应该错过它。因为错误显示缺少数据库。您是否在应用程序中指定了数据库路径？如何指定？我已经使用以下命令完成了：self.dbManager=[[dbManager alloc]initWithDatabaseFileName:@“db.sql”]；在viewdid中load@frincit：是的，这是正确的，之后您必须将文件复制到文档目录确定尝试重置模拟器。重置内容和设置。然后重新运行应用程序。您正在运行示例文件本身吗？或者你自己也修改过吗？因为我已经下载了代码，它在这里运行得非常好。示例文件在这里运行得很好。没有进一步的线索。我们被困在这里，哈哈。你是在运行示例代码本身还是在某个地方对代码进行了调整？