100分了：需要在一个ACCESS表中增加一个字段，如何先判断这个字段存不存在，而后如何添加这个字段
开发环境：VB6+ACCESS2003+ADO
需要在一个ACCESS表中增加一个字段，如何先判断这个字段存不存在，而后如何添加这个字段。
[解决办法]
判断字段下面是一种思路...
[code=V]
Function IsField(pTableName As String, pFieldName As String) As Boolean
'pTableName 要搜索的表名
'pFieldName 要判断的字段名称
Dim cn As ADODB.Connection
Dim rs As ADODB.Recordset
Dim i As Long
Set cn = New ADODB.Connection
cn.Open "......" '连接数据库
Set rs = cn.Execute("Select * From " & Trim(pTableName) & " Where 1=0")
For i = 0 To rs.Fields.Count - 1
If rs.Fields(i).Name = pFieldName Then
IsField = True
Exit For
End If
Next
Set rs = Nothing
Set cn = Nothing
End Function
[/code]
[解决办法]
使用dao, 非常简单:
public function fieldExist(db as Databse,tabName as string,fldName as string) as boolean
dim v
on error goto errr
v=db.tablerefs(tabName).fields(fldname)
fieldExist=true
errr:
end function
[解决办法]
ado还可以用OpenSchema ：
[code=V]
'查询字段是否存在：存在true
Function IsField(pTableName As String, pFieldName As String) As Boolean
Dim cn As ADODB.Connection
Dim rs As ADODB.Recordset
Set cn = New ADODB.Connection
cn.Open "......" '连接数据库
Set rs = cn.OpenSchema(adSchemaColumns, Array(Empty, Empty, pTableName, Empty))
rs.Find "COLUMN_NAME='" & pFieldName & "'"
IsField = Not rs.EOF
Set rs = Nothing
Set cn = Nothing
End Function
[/code]
也简单吧？
[解决办法]
csdn总让人郁闷....
[code=VB.NE]
'查询字段是否存在：存在true
Function IsField(pTableName As String, pFieldName As String) As Boolean
Dim cn As ADODB.Connection
Dim rs As ADODB.Recordset
Set cn = New ADODB.Connection
cn.Open "......" '连接数据库
Set rs = cn.OpenSchema(adSchemaColumns, Array(Empty, Empty, pTableName, Empty))
rs.Find "COLUMN_NAME='" & pFieldName & "'"
IsField = Not rs.EOF
Set rs = Nothing
Set cn = Nothing
End Function
[/code]
