C# 我无法使mySQL Delete命令正常工作
这样我就可以将行插入mySQL数据库。 现在我正试图从数据库中删除行 我将我的代码减少到了最低限度: 您需要一个对MySql.Data.MySqlClient的引用,并使用.Net 4.5.2C# 我无法使mySQL Delete命令正常工作,c#,mysql,sql-delete,C#,Mysql,Sql Delete,这样我就可以将行插入mySQL数据库。 现在我正试图从数据库中删除行 我将我的代码减少到了最低限度: 您需要一个对MySql.Data.MySqlClient的引用,并使用.Net 4.5.2 using System; using System.Data; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using MySql.Data.M
using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MySql.Data.MySqlClient;
namespace StackOverFlow_mySQLTest
{
class Program
{
private static string server = "ds2";
private static string database = "fhem";
private static string user = "fhemdbuser";
private static string passwort = "!2345Abcde";
static void Main(string[] args)
{
MySqlCommand cmd;
MySqlTransaction trans;
MySqlConnection connection;
MySqlConnectionStringBuilder builder = new MySqlConnectionStringBuilder();
builder.Server = server;
builder.Database = database;
builder.UserID = user;
builder.Port = 3307;
builder.Password = passwort;
builder.DefaultCommandTimeout = 120;
builder.UseDefaultCommandTimeoutForEF = true;
connection = new MySqlConnection(builder.ConnectionString);
// Datenbank öffnen
connection.Open();
MySqlCommand selectCmdCurrentTest = new MySqlCommand("select `TIMESTAMP`, `DEVICE`, `TYPE`, `EVENT`, `READING`, `VALUE`, `UNIT` from currentTest;", connection);
MySqlDataAdapter dataAdapterCurrentTest = new MySqlDataAdapter(selectCmdCurrentTest);
MySqlCommand updateCmd = new MySqlCommand("update `currentTest` set `TIMESTAMP`= @p1,`DEVICE`= @p2,`TYPE`= @p3,`EVENT`= @p4,`READING`= @p5,`VALUE`= @p6,`UNIT`= @p7", connection);
MySqlParameter p1, p2, p3, p4, p5, p6, p7;
p1 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Timestamp", ParameterName = "@p1", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.DateTime};
p2 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Device", ParameterName = "@p2", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString};
p3 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Type", ParameterName = "@p3", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString};
p4 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Event", ParameterName = "@p4", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString};
p5 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Reading", ParameterName = "@p5", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString};
p6 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Value", ParameterName = "@p6", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString};
p7 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Unit", ParameterName = "@p7", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString};
updateCmd.Parameters.AddRange(new[] { p1, p2, p3, p4, p5, p6, p7 });
dataAdapterCurrentTest.UpdateCommand = updateCmd;
MySqlCommand deleteCmd = new MySqlCommand("delete from `currentTest` where `TIMESTAMP`like @p1 and `DEVICE` like @p2 and `TYPE` like @p3 and `EVENT` like @p4 and `READING` like @p5 and `VALUE` like @p6 and `UNIT` like @p7", connection);
p1 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Timestamp", ParameterName = "@p1", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.DateTime, SourceVersion = DataRowVersion.Original };
p2 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Device", ParameterName = "@p2", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p3 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Type", ParameterName = "@p3", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p4 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Event", ParameterName = "@p4", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p5 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Reading", ParameterName = "@p5", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p6 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Value", ParameterName = "@p6", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p7 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Unit", ParameterName = "@p7", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
deleteCmd.Parameters.AddRange(new[] { p1, p2, p3, p4, p5, p6, p7 });
dataAdapterCurrentTest.DeleteCommand = deleteCmd;
DataSet ds = new DataSet();
dataAdapterCurrentTest.Fill(ds, "currentTest");
此处,ds
中的表格仍然为空
for (int i = 0; i < 10; i++)
{
DataRow newrow = ds.Tables["currentTest"].NewRow();
newrow["Timestamp"] = DateTime.Now;
newrow["Device"] = "Device" + DateTime.Now.Millisecond.ToString();
newrow["TYPE"] = "Type" + DateTime.Now.Millisecond.ToString();
newrow["EVENT"] = "Event" + DateTime.Now.Millisecond.ToString();
newrow["READING"] = "Reading" + DateTime.Now.Millisecond.ToString();
newrow["VALUE"] = "Value" + DateTime.Now.Millisecond.ToString();
newrow["UNIT"] = "Unit" + DateTime.Now.Millisecond.ToString();
ds.Tables["currentTest"].Rows.Add(newrow);
}
new MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables["currentTest"]);
ds.Tables["currentTest"].AcceptChanges();
尽管如此,ds
仍有10行包含预期数据(与之前相同,但日期设置为2020-07-01)
for (int i = 0; i < ds.Tables["currentTest"].Rows.Count; i++)
{
ds.Tables["currentTest"].Rows[i].Delete();
}
new MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables["currentTest"]);
我不知道如何创建delete命令以使其正常工作,
我自己找到了解决办法。
问题似乎是您必须用数据库中的数据再次填充数据集。。。
下面是附加的代码部分:
在数据集ds=new DataSet()之前;
:
MySqlParameter p1, p2, p3, p4, p5, p6, p7;
MySqlCommand deleteCmd = new MySqlCommand("delete from `currentTest` where `TIMESTAMP`like @p1 and `DEVICE` like @p2 and `TYPE` like @p3 and `EVENT` like @p4 and `READING` like @p5 and `VALUE` like @p6 and `UNIT` like @p7", conn);
p1 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Timestamp", ParameterName = "@p1", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.DateTime, SourceVersion = DataRowVersion.Original };
p2 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Device", ParameterName = "@p2", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p3 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Type", ParameterName = "@p3", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p4 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Event", ParameterName = "@p4", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p5 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Reading", ParameterName = "@p5", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p6 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Value", ParameterName = "@p6", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p7 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Unit", ParameterName = "@p7", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
deleteCmd.Parameters.AddRange(new[] { p1, p2, p3, p4, p5, p6, p7 });
deleteCmd.UpdatedRowSource = UpdateRowSource.FirstReturnedRecord;
dataAdapterCurrentTest.DeleteCommand = deleteCmd;
添加行后:
new MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables["currentTest"]);
ds.Tables["currentTest"].AcceptChanges();
ds.Tables["currentTest"].Clear();
dataAdapterCurrentTest.Fill(ds, "currentTest");
for (int i = 0; i < 20; i++)
{
ds.Tables["currentTest"].Rows[i].Delete();
}
new MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables["currentTest"]);
ds.Tables["currentTest"].AcceptChanges();
ds.Tables["currentTest"].Clear();
dataAdapterCurrentTest.Fill(ds, "currentTest");
新建MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables[“currentTest”]);
表[“currentTest”].AcceptChanges();
ds.表格[“currentTest”].Clear();
dataAdapterCurrentTest.Fill(ds,“currentTest”);
对于(int i=0;i<20;i++)
{
ds.Tables[“currentTest”].Rows[i].Delete();
}
新的MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables[“currentTest”]);
表[“currentTest”].AcceptChanges();
ds.表格[“currentTest”].Clear();
dataAdapterCurrentTest.Fill(ds,“currentTest”);
好的,
我自己找到了解决办法。
问题似乎是您必须用数据库中的数据再次填充数据集。。。
下面是附加的代码部分:
在数据集ds=new DataSet()之前;
:
MySqlParameter p1, p2, p3, p4, p5, p6, p7;
MySqlCommand deleteCmd = new MySqlCommand("delete from `currentTest` where `TIMESTAMP`like @p1 and `DEVICE` like @p2 and `TYPE` like @p3 and `EVENT` like @p4 and `READING` like @p5 and `VALUE` like @p6 and `UNIT` like @p7", conn);
p1 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Timestamp", ParameterName = "@p1", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.DateTime, SourceVersion = DataRowVersion.Original };
p2 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Device", ParameterName = "@p2", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p3 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Type", ParameterName = "@p3", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p4 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Event", ParameterName = "@p4", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p5 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Reading", ParameterName = "@p5", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p6 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Value", ParameterName = "@p6", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
p7 = new MySql.Data.MySqlClient.MySqlParameter() { SourceColumn = "Unit", ParameterName = "@p7", MySqlDbType = MySql.Data.MySqlClient.MySqlDbType.VarString, SourceVersion = DataRowVersion.Original };
deleteCmd.Parameters.AddRange(new[] { p1, p2, p3, p4, p5, p6, p7 });
deleteCmd.UpdatedRowSource = UpdateRowSource.FirstReturnedRecord;
dataAdapterCurrentTest.DeleteCommand = deleteCmd;
添加行后:
new MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables["currentTest"]);
ds.Tables["currentTest"].AcceptChanges();
ds.Tables["currentTest"].Clear();
dataAdapterCurrentTest.Fill(ds, "currentTest");
for (int i = 0; i < 20; i++)
{
ds.Tables["currentTest"].Rows[i].Delete();
}
new MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables["currentTest"]);
ds.Tables["currentTest"].AcceptChanges();
ds.Tables["currentTest"].Clear();
dataAdapterCurrentTest.Fill(ds, "currentTest");
新建MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables[“currentTest”]);
表[“currentTest”].AcceptChanges();
ds.表格[“currentTest”].Clear();
dataAdapterCurrentTest.Fill(ds,“currentTest”);
对于(int i=0;i<20;i++)
{
ds.Tables[“currentTest”].Rows[i].Delete();
}
新的MySqlCommandBuilder(dataAdapterCurrentTest);
dataAdapterCurrentTest.Update(ds.Tables[“currentTest”]);
表[“currentTest”].AcceptChanges();
ds.表格[“currentTest”].Clear();
dataAdapterCurrentTest.Fill(ds,“currentTest”);
值得注意的是,你的数据访问策略已经过时了。考虑使用实体框架核心或者是一个类似于ORM的小说家。我想你可以在这里找到答案。Robththavey:如果使用起来很简单,我会使用EFC。使用MSSQL或LoalDB使用EF,但是我不能让它与MySQL一起工作。所以我被困在这里。但是C考虑到我实现的目的,它仍然可以完成任务。@Ramin,我读过这篇文章,但是你一次删除一个数据行,这不是很低效吗?我想让一个实现使用数据集、数据表和数据行来处理我的数据。Dapper与任何实现DbConnection
,的数据库一起工作。这是为了什么值得一提的是,你的数据访问策略已经过时了。考虑使用实体框架核心或者一个类似于微细ORM的DaPror。我想你可以在这里找到答案。Robththavey:如果它很容易,我会使用EFC。使用EngsMsSQL或LoalDB工作,但是我不能让它与MySQL一起工作。所以我被困在这里。但是考虑到PrPOS。在我的实现中,它仍然起作用。@Ramin,我读过这篇文章,但是你一次删除一行数据,这不是很低效吗?我希望有一个使用数据集、数据表和数据行来处理我的数据的实现。Dapper可以与任何实现DbConnection
的数据库一起工作。