如何用adox取到某个字段它是否允许null

[SonicOne]

我根据adox的帮助，尝试察看objADOX_Column.Attributes属性，但它并非反映数据结构的真实情况。谢谢各位指点一二。

[蒋晟]

depend on the database engine

in Jet 4.0, it is the Nullable property of the column object.

http://www.codeguru.com/Cpp/data/mfc_database/ado/article.php/c4343/

[northwolves]

' 引用 Microsoft ADO Ext. 2.x for DDL & Security

Private Sub Command1_Click()
Dim mycat As New ADOX.Catalog
Dim mytable As New ADOX.Table
'
mycat.ActiveConnection = "Provider=MicroSoft.Jet.OLEDB.4.0;Data Source=e:\wbzx.MDB"
Set mytable = mycat.Tables("wbx")
MsgBox mytable.Columns("word").Properties("Jet OLEDB:Allow Zero Length").Value

End Sub

[myhgyp]

' 引用 Microsoft ADO Ext. 2.x for DDL & Security

Private Sub Command1_Click()
Dim mycat As New ADOX.Catalog
Dim mytable As New ADOX.Table
'
mycat.ActiveConnection = "Provider=MicroSoft.Jet.OLEDB.4.0;Data Source=e:\wbzx.MDB"
Set mytable = mycat.Tables("wbx")
MsgBox mytable.Columns("word").Properties("Nullable").Value '是否允许为Null

End Sub

[winehero]

用列对象.Attributes是否等于adColNullable判断不行吗？！

if 列对象.Attributes=adColNullable then
msgbox "列可为NULL"
else
msgbox "列不可为NULL"
end if

[蒋晟]

Allow Zero Length是是否允许长度为0的字符串，和null还是有区别的