今天学习在VB.NET上操作SQL SERVER数据库，为防止将来忘记，记录于此。
一、清空某张表中的全部数据
Dim cn As New SqlConnection("Server=" & g_DatabaseServerIp & ";Initial Catalog=" & g_DatabaseName & ";UID=" & g_DatabaseUser & ";Pwd=" & g_DatabaseUserPassword)
cn.Open()
Dim cmd As New SqlCommand
cmd.Connection = cn
cmd.CommandText = "delete from tbMergeIns"
cmd.ExecuteNonQuery()
cmd.Dispose() '释放资源
cn.Close()
cn.Dispose() '释放资源 感觉很像VB6里的 set xx=nothing
MessageBox.Show("全部删除完成")
二 向某张表插入数据
Dim cn As New SqlConnection("Server=" & g_DatabaseServerIp & ";Initial Catalog=" & g_DatabaseName & ";UID=" & g_DatabaseUser & ";Pwd=" & g_DatabaseUserPassword)
cn.Open()
Dim cmd As New SqlCommand()
cmd.Connection = cn
Dim Id As String
Dim SendCompany As String
Dim TotalWeightLock As Integer
id = "201906140001"
sendcompany = "a"
totalweightlock = 1
cmd.CommandText = "insert into tbMergeIns (id,sendcompany,totalweightlock) values(" & Chr(39) & Id & Chr(39) & "," & Chr(39) & SendCompany & Chr(39) & "," & TotalWeightLock & ")"
cmd.ExecuteNonQuery()
Id = "201906140002"
SendCompany = "aa"
TotalWeightLock = 1
cmd.CommandText = "insert into tbMergeIns (id,sendcompany,totalweightlock) values(" & Chr(39) & Id & Chr(39) & "," & Chr(39) & SendCompany & Chr(39) & "," & TotalWeightLock & ")"
cmd.ExecuteNonQuery()
Id = "201906140003"
SendCompany = "aaa"
TotalWeightLock = 1
cmd.CommandText = "insert into tbMergeIns (id,sendcompany,totalweightlock) values(" & Chr(39) & Id & Chr(39) & "," & Chr(39) & SendCompany & Chr(39) & "," & TotalWeightLock & ")"
cmd.ExecuteNonQuery()
cmd.Dispose()
cn.Close()
cn.Dispose()
MessageBox.Show("插入3行测试完成")
三 修改
Dim cn As New SqlConnection("Server=" & g_DatabaseServerIp & ";Initial Catalog=" & g_DatabaseName & ";UID=" & g_DatabaseUser & ";Pwd=" & g_DatabaseUserPassword)
cn.Open()
Dim cmd As New SqlCommand()
cmd.Connection = cn
Dim strNewSendCompany As String
strNewSendCompany = "aaaaaaa"
Dim strCondition As String
strCondition = "a"
cmd.CommandText = "update tbMergeIns set sendcompany=" & Chr(39) & strNewSendCompany & Chr(39) & " where sendcompany=" & Chr(39) & strCondition & Chr(39)
cmd.ExecuteNonQuery()
cmd.Dispose()
cn.Close()
cn.Dispose()
MessageBox.Show("修改测试完成")
四 删除
Dim cn As New SqlConnection("Server=" & g_DatabaseServerIp & ";Initial Catalog=" & g_DatabaseName & ";UID=" & g_DatabaseUser & ";Pwd=" & g_DatabaseUserPassword)
cn.Open()
Dim cmd As New SqlCommand()
cmd.Connection = cn
Dim strCondition As String
strCondition = "aaaaaaa"
cmd.CommandText = "delete from tbMergeIns where sendcompany=" & Chr(39) & strCondition & Chr(39)
cmd.ExecuteNonQuery()
cmd.Dispose()
cn.Close()
cn.Dispose()
MessageBox.Show("删除测试完成")
五 查询
Dim cn As New SqlConnection("Server=" & g_DatabaseServerIp & ";Initial Catalog=" & g_DatabaseName & ";UID=" & g_DatabaseUser & ";Pwd=" & g_DatabaseUserPassword)
cn.Open()
Dim strIDCondition As String
strIDCondition = "201906140002"
Dim iTotalWeightLockCondition As Integer
iTotalWeightLockCondition = 1
Dim cmd As New SqlCommand()
cmd.Connection = cn
cmd.CommandText = "select * from tbMergeIns where id=" & Chr(39) & strIDCondition & Chr(39) & " and TotalWeightLock=" & iTotalWeightLockCondition
Dim dr As SqlDataReader
dr = cmd.ExecuteReader()
If dr.HasRows() = True Then
Do While dr.Read() = True '如果有记录，就循环打印符合条件的记录的address字段中内容
Debug.Print(dr.Item("id") & " " & dr.Item("sendcompany") & " " & dr.Item("totalweightlock"))
Loop
Else
MessageBox.Show("搜索失败")
End If
dr.Close()
'结果为
'201906140002 aa 1
'查询全部
cmd.CommandText = "select * from tbMergeIns order by id"
dr = cmd.ExecuteReader()
If dr.HasRows() = True Then
Do While dr.Read() = True '如果有记录，就循环打印符合条件的记录的address字段中内容
Debug.Print(dr.Item("id") & " " & dr.Item("sendcompany") & " " & dr.Item("totalweightlock"))
Loop
End If
'结果为
' 201906140002 aa 1
' 201906140003 aaa 1
dr.Close()
cmd.Dispose()
cn.Close()
cn.Dispose()
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原文链接：https://blog.csdn.net/iamtsfw/article/details/91984227
