ex.Message = "对于不返回任何键列信息的 SelectCommand,不支持 UpdateCommand 的动态 SQL 生成。"
时间: 2024-06-03 21:06:45 浏览: 11
This message is in Chinese and it roughly translates to:
"For SelectCommand that does not return any key column information, dynamic SQL generation for UpdateCommand is not supported."
相关问题
SQL语句执行错误:对于不返回任何键列信息的 SelectCommand,不支持 UpdateCommand 的动态 SQL 生成。
这个错误通常是由于在使用 DataAdapter 更新数据时,DataAdapter 没有正确识别主键或没有正确设置适配器的 UpdateCommand 属性所导致的。这可能是由于以下原因之一:
1. 数据库表中没有主键,或者主键被更改了。DataAdapter 需要知道主键以便能够正确地生成 UpdateCommand。
2. 在生成 DataAdapter 时,没有设置适配器的 SelectCommand 属性。DataAdapter 需要知道如何选择要更新的数据行。
为了解决这个问题,你可以尝试以下步骤:
1. 确认数据库表中有主键,并且主键没有被更改。如果需要,可以使用 SQL 语句 ALTER TABLE 添加主键。
2. 确认 DataAdapter 的 SelectCommand 属性被正确设置。SelectCommand 应该返回所有要更新的数据行,并且应该返回主键列。
3. 确认 DataAdapter 的 UpdateCommand 属性被正确设置。UpdateCommand 应该包括所有要更新的列,并且应该使用主键列作为 WHERE 子句。
如果你仍然遇到问题,请检查你的 SQL 语句和 DataAdapter 配置,并确保它们正确匹配。
Imports System.Data.OleDb Public Class Form3 Dim con As New OleDbConnection Dim adp As New OleDbDataAdapter Dim ds As New DataSet Private Sub Form3_Load(sender As Object, e As EventArgs) Handles MyBase.Load con.ConnectionString = "Provider=SQLOLEDB;Data Source=.;Integrated Security=SSPI;Initial Catalog=students" Dim selectcmd As New OleDbCommand selectcmd.CommandText = "select * from student" selectcmd.Connection = con adp.SelectCommand = selectcmd adp.Fill(ds, "Table") End Sub Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click For Each txt As TextBox In Me.Controls.OfType(Of TextBox)() txt.Text = "" Next For Each combo As ComboBox In Me.Controls.OfType(Of ComboBox)() combo.Text = "" Next End Sub Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click Dim insecmd As New OleDbCommand Dim Vs As String = TextBox1.Text & "','" & TextBox2.Text & "','" & ComboBox1.Text & "','" & ComboBox2.Text & "'," & TextBox3.Text & ",'" & ComboBox3.Text & ComboBox4.Text & ComboBox5.Text & "','" & TextBox4.Text & "','" & ComboBox6.Text & "','" & TextBox5.Text & "')" insecmd.CommandText = "insert into student values('" & Vs insecmd.Connection = con adp.InsertCommand = insecmd adp.Update(ds) End Sub End Class这段代码有什么问题
这段代码有几个问题:
1. 连接字符串是针对 SQL Server 的,而不是 Access 数据库。应该使用 Access 数据库的连接字符串,例如:
```
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MyDatabase.mdb"
```
2. 在插入数据时,字符串值应该使用参数化查询,而不是将值直接拼接到 SQL 语句中。这样可以避免 SQL 注入攻击,并且可以自动处理特殊字符的转义。应该改为类似下面的语句:
```
insecmd.CommandText = "insert into student values(?, ?, ?, ?, ?, ?, ?, ?, ?)"
insecmd.Parameters.AddWithValue("param1", TextBox1.Text)
insecmd.Parameters.AddWithValue("param2", TextBox2.Text)
'...
```
3. 在清空表单数据时,应该检查控件的类型是否为 TextBox 或 ComboBox,否则可能会出现异常。可以改为类似下面的语句:
```
For Each ctrl As Control In Me.Controls
If TypeOf ctrl Is TextBox Then
DirectCast(ctrl, TextBox).Text = ""
ElseIf TypeOf ctrl Is ComboBox Then
DirectCast(ctrl, ComboBox).Text = ""
End If
Next
```
4. 在插入数据后应该更新 DataSet 中的数据,以便在下一次查询中可以看到新插入的记录。可以改为类似下面的语句:
```
adp.Update(ds, "Table")
```
根据上述建议,可以将代码修改为:
```
Imports System.Data.OleDb
Public Class Form3
Dim con As New OleDbConnection
Dim adp As New OleDbDataAdapter
Dim ds As New DataSet
Private Sub Form3_Load(sender As Object, e As EventArgs) Handles MyBase.Load
con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MyDatabase.mdb"
Dim selectcmd As New OleDbCommand
selectcmd.CommandText = "select * from student"
selectcmd.Connection = con
adp.SelectCommand = selectcmd
adp.Fill(ds, "Table")
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
For Each ctrl As Control In Me.Controls
If TypeOf ctrl Is TextBox Then
DirectCast(ctrl, TextBox).Text = ""
ElseIf TypeOf ctrl Is ComboBox Then
DirectCast(ctrl, ComboBox).Text = ""
End If
Next
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim insecmd As New OleDbCommand
insecmd.CommandText = "insert into student values(?, ?, ?, ?, ?, ?, ?, ?, ?)"
insecmd.Parameters.AddWithValue("param1", TextBox1.Text)
insecmd.Parameters.AddWithValue("param2", TextBox2.Text)
insecmd.Parameters.AddWithValue("param3", ComboBox1.Text)
insecmd.Parameters.AddWithValue("param4", ComboBox2.Text)
insecmd.Parameters.AddWithValue("param5", TextBox3.Text)
insecmd.Parameters.AddWithValue("param6", ComboBox3.Text & ComboBox4.Text & ComboBox5.Text)
insecmd.Parameters.AddWithValue("param7", TextBox4.Text)
insecmd.Parameters.AddWithValue("param8", ComboBox6.Text)
insecmd.Parameters.AddWithValue("param9", TextBox5.Text)
insecmd.Connection = con
adp.InsertCommand = insecmd
adp.Update(ds, "Table")
End Sub
End Class
```