如何将 ACCESS 数据库查询到变量

Question

我正在尝试查询访问数据库以查找数据库中是否存在一行以及 IsManager 的值是否为 True。我是使用数据库的新手，所以任何帮助都很好谢谢你们:) <3

    Try
        Dim SQL As String
        Dim CMD As New OleDb.OleDbCommand
        Dim DT As New DataTable
        Dim D_A As New OleDb.OleDbDataAdapter
        MainMenu.Con.Open()

        SQL = ("SELECT * FROM Staff WHERE Login = " & ID)
        CMD.Connection = MainMenu.Con
        CMD.CommandText = SQL
        D_A.SelectCommand = CMD

        D_A.Fill(DT)
    Catch ex As Exception
        MsgBox(ex.Message)
    Finally
        MainMenu.Con.Close()
    End Try

Answer 1

不要先填充数据表，然后再检索其中的字段。在变量中插入您想要获得的值。

Dim IsManager as Boolean
Try
    Dim SQL As String
    Dim CMD As New OleDb.OleDbCommand
    Dim D_A As New OleDb.OleDbDataAdapter    

    SQL = ("SELECT IsManager FROM Staff WHERE Login = " & ID)
    CMD.Connection = MainMenu.Con
    CMD.CommandText = SQL
    D_A.SelectCommand = CMD

    MainMenu.Con.Open()

    Dim Dr as OleDbDataReader = CMD.ExecuteReader

    Dr.Read()
    IsManager = Dr.Item("IsManager")
    Dr.Close()

Catch ex As Exception
    MsgBox(ex.Message)
Finally
    MainMenu.Con.Close()
End Try

如何将 ACCESS 数据库查询到变量

How to query an ACCESS database to a variable

sql

vb.net

ms-access