我在通过 C# 将值插入 MySQL 数据库时遇到了一个特殊的问题。
我有四个控件，我从 WPF 表单中收集数据；三个是文本框，一个是日期选择器。
连接到数据库后，填写表格。我一直在使用以下值：
txtIdNumber: 1
dtpDateOfBirth = 7/30/2013 (today)
txtMenarcheAge = 14
txtSport1 = Soccer
这是它正在被冲洗的代码：
if (MessageBox.Show("Are you sure you want to submit these changes to the database? Just making sure...", "", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
{
//database logic HERE.
DateTime birthday = (DateTime)dtpDateOfBirth.SelectedDate;
string birthdayString = birthday.ToString("yyyy-MM-dd");
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = conn;
Console.WriteLine(Convert.ToString(dtpDateOfBirth.SelectedDate));
//check each box that MUST contain an entry, then submit it to the database if it's correct
if (txtIdNumber.Text != "" && dtpDateOfBirth.SelectedDate != null)
{
cmd.CommandText = "INSERT INTO TestSubject VALUES(NULL, @subjectId, @subjectDOB)";
cmd.Prepare();
cmd.Parameters.AddWithValue("@subjectId", txtIdNumber.Text);
cmd.Parameters.AddWithValue("@subjectDOB", "'" + birthdayString + "'");
Console.WriteLine(birthdayString);
Console.WriteLine(cmd.Parameters["@subjectId"].Value);
Console.WriteLine(cmd.Parameters["@subjectDOB"].Value);
cmd.ExecuteNonQuery();
}
else if (txtIdNumber.Text != "" && dtpDateOfBirth.SelectedDate != null && txtMenarcheAge.Text != "")
{
cmd.CommandText = "INSERT INTO TestSubject VALUES(@subjectId, @subjectDOB, @subjectMenarche)";
cmd.Prepare();
cmd.Parameters.AddWithValue("@subjectId", txtIdNumber.Text);
cmd.Parameters.AddWithValue("@subjectDOB", birthdayString);
cmd.Parameters.AddWithValue("@subjectMenarche", txtMenarcheAge.Text);
cmd.ExecuteNonQuery();
}
}
首先，我将 datepicker 中的 datetime 转换为类似于 MySQL 使用的东西。然后，我将其转换为字符串。
接下来，我设置了必要的MySqlCommand对象，并将其Connection属性设置为conn，这是在另一个类中建立的。
之后是检查以确保表格有效。必须提供测试对象的 ID 号和生日，因此首先对其进行检查。这就是我们遇到麻烦的地方。我对 MySQL 中的prepared statements 比较陌生，所以我使用这个例子来让自己有方向感。在街区
cmd.CommandText = "INSERT INTO TestSubject VALUES(NULL, @subjectId, @subjectDOB)";
cmd.Prepare();
cmd.Parameters.AddWithValue("@subjectId", txtIdNumber.Text);
cmd.Parameters.AddWithValue("@subjectDOB", "'" + birthdayString + "'");
Console.WriteLine(birthdayString);
Console.WriteLine(cmd.Parameters["@subjectId"].Value);
cmd.ExecuteNonQuery();
我在运行时遇到以下异常：
MySql.Data.MySqlClient.MySqlException was unhandled
HResult=-2147467259
Message=Column 'subjectId' cannot be null
Source=MySql.Data
ErrorCode=-2147467259
Number=1048
StackTrace:
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId)
at MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int64& insertedId)
at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force)
at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
at mu_kinect_project_data_form.MainWindow.btnSubmitWholeForm_Click(Object sender, RoutedEventArgs e) in c:\Users\asm3kf.TIGERS\Documents\mu_kinect_project_data_form\mu_kinect_project_data_form\MainWindow.xaml.cs:line 315
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.Controls.Button.OnClick()
at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run()
at mu_kinect_project_data_form.App.Main() in c:\Users\asm3kf.TIGERS\Documents\mu_kinect_project_data_form\mu_kinect_project_data_form\obj\Debug\App.g.cs:line 0
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
我不确定它是从哪里得到subjectId的null。它正在接收输入。
编辑：添加 MySQL 脚本，因为这是拼图的一半。
SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL';
CREATE SCHEMA IF NOT EXISTS `kinect7` DEFAULT CHARACTER SET utf8 ;
USE `kinect7` ;
-- -----------------------------------------------------
-- Table `kinect7`.`TestSubject`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `kinect7`.`TestSubject` (
`subjectId` INT(11) NOT NULL ,
`subjectDOB` DATE NOT NULL ,
`subjectMenarche` DATE NULL DEFAULT NULL ,
PRIMARY KEY (`subjectId`) ,
UNIQUE INDEX `subjectId_UNIQUE` (`subjectId` ASC) )
ENGINE = InnoDB
COMMENT = ' ';
-- -----------------------------------------------------
-- Table `kinect7`.`SubjectInjury`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `kinect7`.`SubjectInjury` (
`injuryDate` DATE NOT NULL ,
`injuryKnee` VARCHAR(5) NOT NULL ,
`TestSubject_subjectId` INT(11) NOT NULL ,
`surgeryPerformed` VARCHAR(10) NULL,
PRIMARY KEY (`TestSubject_subjectId`, `injuryKnee`, `injuryDate`) ,
CONSTRAINT `fk_PreviousInjury_TestSubject1`
FOREIGN KEY (`TestSubject_subjectId` )
REFERENCES `kinect7`.`TestSubject` (`subjectId` )
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
-- -----------------------------------------------------
-- Table `kinect7`.`SubjectJumps`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `kinect7`.`SubjectJumps` (
`jumpDate` DATETIME NOT NULL ,
`rightAnkleRatio` DECIMAL(6,3) NULL DEFAULT NULL ,
`leftAnkleRatio` DECIMAL(6,3) NULL DEFAULT NULL ,
`rightKneeValgus` DECIMAL(6,3) NULL DEFAULT NULL ,
`leftKneeValgus` DECIMAL(6,3) NULL DEFAULT NULL ,
`rightKneeFlexion` DECIMAL(6,3) NULL DEFAULT NULL ,
`leftKneeFlexion` DECIMAL(6,3) NULL DEFAULT NULL ,
`testSubject_subjectId` INT(11) NOT NULL ,
PRIMARY KEY (`jumpDate`, `testSubject_subjectId`) ,
INDEX `fk_subjectJumps_testSubject_idx` (`testSubject_subjectId` ASC) ,
CONSTRAINT `fk_subjectJumps_testSubject`
FOREIGN KEY (`testSubject_subjectId` )
REFERENCES `kinect7`.`TestSubject` (`subjectId` )
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
-- -----------------------------------------------------
-- Table `kinect7`.`SubjectSports`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `kinect7`.`SubjectSports` (
`sport` VARCHAR(10) NOT NULL ,
`TestSubject_subjectId` INT(11) NOT NULL ,
PRIMARY KEY (`TestSubject_subjectId`, `sport`) ,
CONSTRAINT `fk_SubjectSports_TestSubject1`
FOREIGN KEY (`TestSubject_subjectId` )
REFERENCES `kinect7`.`TestSubject` (`subjectId` )
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;
SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;