最近发现一段代码在处理空值上不是很好,分别写了2段代码,一个是我的,一个是兄弟的,哪个好点呢?
'
<summary>将空字段转换为空串</summary>
'
<param name="Field">字段实例</param>
'
<return>字段内容</return>
Public
Function
ConvertNull2String(Field
As
ADODB.Field)
As
Variant
Require Me.IsInstance(Field), Me,
"
ConvertNull2String
"
,
"
Field必须实例化
"
If
Field.Type
=
adVarWChar
Or
Field.Type
=
adChar
Then
ConvertNull2String
=
Field.Value
&
""
Else
ConvertNull2String
=
Field.Value
End
If
End Function

'
取得指定字段得值内容
Public
Function
GetFieldValue(Field
As
Field, Optional
IsNumeric
As
Boolean
=
False
)
As
Variant
On
Error
GoTo
e
If
Not
Field
Is
Nothing
Then
If
IsNull
(Field.Value)
Then
If
IsNumeric
Then
GetFieldValue
=
0
Else
GetFieldValue
=
""
End
If
Else
GetFieldValue
=
Field.Value
End
If
Else
GetFieldValue
=
""
End
If
Exit
Function
e:
GetFieldValue
=
""
End Function
当然如果在Sql语句里边处理好了,就更棒了,向下边这样:
SELECT A, ISNULL(B, '0') AS B FROM tNulls
相关文章:
http://www.access-cn.com/Article/Class5/Class28/Class30/200508/1744.html
http://www.zdnet.com.cn/developer/database/story/0,3800066906,39412365,00.htm
http://unruledboy.cnblogs.com/archive/2004/06/27/18988.aspx
本文探讨了两种处理数据库字段中空值的方法,一种是通过VBA函数进行转换,另一种是在SQL语句中直接处理。并提供了具体实现代码及推荐做法。
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