一个整合SQL语句的类

我们在写ASP数据库程序的时候，通常都会用到SQL语句，而在增加数据和更新数据的时候，通常会使用一下方式：insert into message (incept,sender,title,content,sendtime,flag,issend) values ('"&incept(i)&"','"&membername&"','"&title&"','"&message&"',Now(),0,1)当字段比较多的时候，而且更新的表比较多的时候，修改起来会比较麻烦，而且查找错误也比较困难。使用这个SQL类后可以简化修改，而且查错也比较容易。通过类的AddField函数增加字段名和字段值，可轻松的将字段名和字段值插入SQL语句，然后返回该SQL语句。

下面让我们看看这个类的代码：

<%

class SQLString

'************************************

'变量定义

'************************************

'sTableName ---- 表名

'iSQLType ----SQL语句类型：0-增加，1-更新，2-删除,3-查询

'sWhere ---- 条件

'sOrder ---- 排序方式

'sSQL ----值

Private sTableName,iSQLType,sWhere,sOrder,sSQL

'************************************

'类初始化/结束

'************************************

Private Sub Class_Initialize()

sTableName=""

iSQLType=0

sWhere=""

sOrder=""

sSQL=""

End Sub

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Private Sub Class_Terminate()

End Sub

'************************************

'属性

'************************************

‘设置表名的属性

Public Property Let TableName(value)

sTableName=value

End Property

‘设置条件

Public Property Let Where(value)

sWhere=value

End Property

‘设置排序方式

Public Property Let Order(value)

sOrder=value

End Property

‘设置查询语句的类型

Public property Let SQLType(value)

iSQLType=value

select case iSQLType

case 0

sSQL="insert into #0 (#1) values (#2)"

case 1

sSQL="update #0 set #1=#2"

case 2

sSQL="delete from #0 "

case 3

sSQL="select #1 from #0 "

end select

End Property

'************************************

'函数

'************************************

'增加字段（字段名称，字段值）

Public Sub AddField(sFieldName,sValue)

select case iSQLType

case 0

sSQL=replace(sSQL,"#1",sFieldName & ",#1")

sSQL=replace(sSQL,"#2","'" & sFieldName & "',#2")

case 1

sSQL=replace(sSQL,"#1",sFieldName)

sSQL=replace(sSQL,"#2","'" & sFieldName & "',#1=#2")

case 3

sSQL=replace(sSQL,"#1",sFieldName & ",#1")

End Select

End Sub

'返回SQL语句

Public Function ReturnSQL()

sSQL=replace(sSQL,"#0",sTableName)

select case iSQLType

case 0

sSQL=replace(sSQL,",#1","")

sSQL=replace(sSQL,",#2","")

case 1

sSQL=replace(sSQL,",#1=#2","")

case 3

sSQL=replace(sSQL,",#1","")

end Select

if sWhere<>"" then

sSQL=sSQL & " where " & sWhere

end if

if sOrder<>"" then

sSQL=sSQL & " order by " & sOrder

end if

ReturnSQL=sSQL

End Function

'清空语句

Public Sub Clear()

sTableName=""

iSQLType=0

sWhere=""

sOrder=""

sSQL=""

End Sub

end class

%>

使用方法：

例句：insert into message (incept,sender,title,content,sendtime,flag,issend) values ('"&incept(i)&"','"&membername&"','"&title&"','"&message&"',Now(),0,1)

set a =new SQLString ‘创建类对象

a.TableName=" message " ‘设置表名为message

a.SQLType=0 ‘设置查询类型为增加记录

a.AddField " incept", incept(i)

a.AddField " sender ", membername

a.AddField " title ", membername

a.AddField " sender ", title

a.AddField " content ", message

a.AddField " sendtime ", sendtime()

a.AddField " flag", 0

a.AddField " issend ", 1

Response.Write a.ReturnSQl

set a=nothing