VB.net 连接 MySql,Use MySql.Data.dll

下载一个叫
mysql-connector-net 的库文件

安装后，会得到一下东西

MySql.Data.dll ，.net 与MySql 连接的桥梁，很好用

MySql.Data.dll ，源码，C# 的，你可以试着完善它

C#和VB.net 的示例程序。

在项目中引用 MySql.Data.dll

再来个 Imports MySql.Data.MySqlClient 就可以使用了

里面有一些对MySql 数据库的一般操作，很容易上手。

下面是我总结出的MySql命令语句，留个档~~

连接：

server={0};user id={1}; password={2}; database=mysql; pooling=false;port={3}

获取：

SELECT * FROM login where UserName='{0}' and Password='{1}'

这里值得注意，文本型的在 Sql 2000 中要使用 like 比较

select ID from login order by ID desc limit 1

可以获得最后一个ID

更新：

UPDATE login SET logintimes='{0}', LastDateTime='{1}' where UserName='{2}'

插入：

INSERT INTO login (id,username,password) VALUES ('{0}','{1}','{2}')

删除：

delete FROM med_entry where ID='{0}'

下面几个自己写的函数，很有用处

'执行 MySql 语句，支持多行。没有返回值

Function ExecuteMySqlCMD(ByRef iconn As MySqlConnection, ByRef MySqlCMD As String, Optional ByRef Err As String = "") As Boolean

MySqlCMD = Strings.Replace(MySqlCMD, Chr(13), "")

MySqlCMD = Strings.Replace(MySqlCMD, Chr(10), "")

Err = ""

Dim reader As MySqlDataReader = Nothing

Dim cmdList() As String

Dim cmd As MySqlCommand = Nothing

Dim i As Integer

cmdList = Strings.Split(MySqlCMD, ";")

If cmdList IsNot Nothing Then

Try

For i = 0 To cmdList.Length - 1

If cmdList(i) = "" Then Continue For

cmd = New MySqlCommand(cmdList(i), iconn)

reader = cmd.ExecuteReader()

reader.Close()

Next

Return True

Catch ex As MySqlException

Err = ex.Message

End Try

End If

Return False

End Function

'执行 MySql 语句，只能一行。返回 DataTable,MySqlDataAdapter,MySqlCommandBuilder

Function ExecuteMySqlCMD(ByRef iconn As MySqlConnection, ByRef MySqlCMD As String, ByRef iDataTable As DataTable, Optional ByRef iMySqlDataAdapter As MySqlDataAdapter = Nothing, Optional ByRef iMySqlCommandBuilder As MySqlCommandBuilder = Nothing, Optional
ByRef Err As String = "") As Boolean

MySqlCMD = Strings.Replace(MySqlCMD, Chr(13), "")

MySqlCMD = Strings.Replace(MySqlCMD, Chr(10), "")

Err = ""

Dim cmdList() As String

cmdList = Strings.Split(MySqlCMD, ";")

If cmdList IsNot Nothing Then

Try

If cmdList(0) = "" Then Exit Try

iDataTable = New DataTable

iMySqlDataAdapter = New MySqlDataAdapter(cmdList(0), iconn)

iMySqlCommandBuilder = New MySqlCommandBuilder(iMySqlDataAdapter)

iMySqlDataAdapter.Fill(iDataTable)

Return True

Catch ex As MySqlException

Err = ex.Message

End Try

End If

Return False

End Function

'检查数据库是否存在

Function CheckDataBase(ByRef iconn As MySqlConnection, ByRef DataBaseName As String, Optional ByRef Err As String = "") As Boolean

Dim reader As MySqlDataReader = Nothing

DataBaseName = DataBaseName.ToLower

Err = ""

Dim cmd As New MySqlCommand("SHOW DATABASES", iconn)

Try

reader = cmd.ExecuteReader()

While (reader.Read())

If reader.GetString(0).ToLower = DataBaseName Then

Return True

End If

End While

Catch ex As MySqlException

Err = ex.Message

Finally

If Not reader Is Nothing Then reader.Close()

End Try

Return False

End Function

'检查数据表是否存在

Function CheckTable(ByRef iconn As MySqlConnection, ByRef DataBaseName As String, ByVal TableName As String, Optional ByRef Err As String = "") As Boolean

Dim reader As MySqlDataReader = Nothing

DataBaseName = DataBaseName.ToLower

TableName = TableName.ToLower

Err = ""

iconn.ChangeDatabase(DataBaseName)

Dim cmd As New MySqlCommand("SHOW TABLES", iconn)

Try

reader = cmd.ExecuteReader()

While (reader.Read())

If reader.GetString(0).ToLower = TableName Then

Return True

End If

End While

Catch ex As MySqlException

Err = ex.Message

Finally

If Not reader Is Nothing Then reader.Close()

End Try

Return False

End Function