на сервере
есть куча
системных функций,
которые возвращают
инфу с сервера
(в т.ч. о полях таблицы
и типе поля)
sp_statistics
sp_tables
если ADO, то есть справка
(ну почему никто
не хочет ее смотреть?)

Type Property Example (Field) (VB)

Dim rstEmployees As ADODB.Recordset
Dim fldLoop As ADODB.Field
Dim strCnn As String

' Open recordset with data from Employees table.
strCnn = "Provider=sqloledb;" & _
"Data Source=srv;Initial Catalog=Pubs;User Id=sa;Password=; "
Set rstEmployees = New ADODB.Recordset
rstEmployees.Open "employee", strCnn, , , adCmdTable

Debug.Print "Fields in Employees Table:" & vbCr

' Enumerate Fields collection of Employees table.
For Each fldLoop In rstEmployees.Fields
Debug.Print " Name: " & fldLoop.Name & vbCr & _
" Type: " & FieldType(fldLoop.Type) & vbCr
Next fldLoop

End Sub

Public Function FieldType(intType As Integer) As String

Select Case intType
Case adChar
FieldType = "adChar"
Case adVarChar
FieldType = "adVarChar"
Case adSmallInt
FieldType = "adSmallInt"
Case adUnsignedTinyInt
FieldType = "adUnsignedTinyInt"
Case adDBTimeStamp
FieldType = "adDBTimeStamp"
End Select

End Function