如何检索实际的 OleDb 表架构（不包括其他表列）

当我运行此代码时，它还会检索表中不存在的一些其他字段。我怎样才能克服这个问题？

Dim conn As New OleDb.OleDbConnection
'Create a connection string for an Access database
Dim strConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=F:\check\a.mdb"
'Attach the connection string to the connection object
conn.ConnectionString = strConnectionString
'Open the connection
conn.Open()
Dim Restrictions() As String = {Nothing, Nothing, selected, Nothing}
Dim CollectionName As String = "Columns"
Dim dt As DataTable = conn.GetSchema(CollectionName, Restrictions)
For Each TableRow As DataRow In dt.Rows
    ComboBox1.Items.Add(TableRow.Item("COLUMN_NAME"))

还检索的附加列是：

1.ID
2.创建日期
3.日期更新
4.Id
5.Lv
6.Name
7.家长ID
8.Type
9.GUID
10.Id

...还有另外 6 个。原始模式仅包含 5 个字段。

你的问题很简单，变量selected有价值Nothing当你将它插入Restrictions()大批。当我运行以下代码时，我只获得名为 [new] 的表的列名称：

Option Strict On

Imports System.Data.OleDb

Module Module1

    Sub Main()
        Dim connStr As String =
                "Provider=Microsoft.ACE.OLEDB.12.0;" &
                "Data Source=C:\Users\Public\test\so34490626\a.mdb"
        Using conn As New OleDbConnection(connStr)
            conn.Open()
            Dim selected As String = "new"
            Dim Restrictions() As String = {Nothing, Nothing, selected, Nothing}
            Dim CollectionName As String = "Columns"
            Dim dt As DataTable = conn.GetSchema(CollectionName, Restrictions)
            For Each TableRow As DataRow In dt.Rows
                Console.WriteLine(TableRow.Item("COLUMN_NAME"))
            Next
        End Using
    End Sub

End Module

结果是：

GENDER
MEMBER OF RISHI PRASAD
NAME OF SADHAK
PROFESSION

然而，当值selected is Nothing ...

Dim selected As String = Nothing

...我得到了你描述的“额外”列

DateCreate
DateUpdate
Id
Lv
Name
ParentId
Type
Attributes
DataType
FieldName
IndexType
SkipColumn
SpecID
Start
Width
DateDelim
DateFourDigitYear
DateLeadingZeros
DateOrder
DecimalPoint
FieldSeparator
FileType
SpecID
SpecName
SpecType
StartRow
TextDelim
TimeDelim
GENDER
MEMBER OF RISHI PRASAD
NAME OF SADHAK
PROFESSION

如果我改变的话，原因就会揭晓Console.WriteLine包含表名称：

Console.WriteLine("[{0}].[{1}]", TableRow.Item("TABLE_NAME"), TableRow.Item("COLUMN_NAME"))

然后我们看到：

[MSysAccessStorage].[DateCreate]
[MSysAccessStorage].[DateUpdate]
[MSysAccessStorage].[Id]
[MSysAccessStorage].[Lv]
[MSysAccessStorage].[Name]
[MSysAccessStorage].[ParentId]
[MSysAccessStorage].[Type]
[MSysIMEXColumns].[Attributes]
[MSysIMEXColumns].[DataType]
[MSysIMEXColumns].[FieldName]
[MSysIMEXColumns].[IndexType]
[MSysIMEXColumns].[SkipColumn]
[MSysIMEXColumns].[SpecID]
[MSysIMEXColumns].[Start]
[MSysIMEXColumns].[Width]
[MSysIMEXSpecs].[DateDelim]
[MSysIMEXSpecs].[DateFourDigitYear]
[MSysIMEXSpecs].[DateLeadingZeros]
[MSysIMEXSpecs].[DateOrder]
[MSysIMEXSpecs].[DecimalPoint]
[MSysIMEXSpecs].[FieldSeparator]
[MSysIMEXSpecs].[FileType]
[MSysIMEXSpecs].[SpecID]
[MSysIMEXSpecs].[SpecName]
[MSysIMEXSpecs].[SpecType]
[MSysIMEXSpecs].[StartRow]
[MSysIMEXSpecs].[TextDelim]
[MSysIMEXSpecs].[TimeDelim]
[new].[GENDER]
[new].[MEMBER OF RISHI PRASAD]
[new].[NAME OF SADHAK]
[new].[PROFESSION]

“MSys*”表是默认情况下隐藏在 Access 用户界面中的系统表。