写自己的代码自动生成模板

你软件中有多少代码是自动生成？　也许你会说，自动生成的代码就是重复代码，是程序本身有问题，但是数据库开发，有些代码不是重复代码，但又需要自动生成。需要自动生成的原因是因为数据库本身包含了大量的信息（也许你又会说了，class->database才是正道)，不是重复代码的原因是因为每个对象的信息又都是不一样的。

　　很多自动代码生成的软件都是通过简单模板来实现的，通过一些自定义的TAG来实现一定的控制，我早期的ceg就是这样的，它伴随着我几个O/R Mapping框架的应用。后来，我的sinolib中的映射XML文件同样需要自动生成，可是ceg的简单模板已经无法再支持映射文件的灵活性了。

　　于是CodeDG就不得不出来了，它使用了script control来完成脚本解析，实现了代码生成的真正灵活，并且以统一的接口向脚本提供不同平台的数据库结构对象的信息。

以下是sinolib的XML映射的例子：

<?xml version=”1.0″ encoding = “GB2312″ ?>
<sino-mapping>
    <class name = “AppRole”>
        <property name = “uid” extname = “唯一识别码” type=”string”  key=”primary”/>
        <property name = “code” extname = “简码” type=”string”/>
        <property name = “name” extname = “名称” type=”string” notnull=”true”/>
        <property name = “remark” extname = “备注” type=”string”/>
        <property name = “isdelete” extname = “删除标志” type=”boolean” notnull=”true”/>
    </class>
</sino-mapping>

这是一CodeDG内置的一个示例脚本：

This is a example script template.
You can write script as same as what’s in ASP.

<%
‘test function
function max(a,b)
    max = iif(a>b,a,b)
end function

max_value = max(1,2)
‘msgbox max_value

response.write “Table:“ &  table.name & vbcrlf
response.write “Comment:“ &  table.description & vbcrlf
response.write “Column count:“ &  table.columns.count & vbcrlf

response.write “========Traverse all column’s property=========“ & vbcrlf

for each cm in Table.columns.items

%>column:<%
    response.write vbtab  & cm.name
    response.write vbcrlf
%>    Primary Key:<%
    response.write vbtab  & cm.pk
    response.write vbcrlf
%>    Auto Identity:<%
    response.write vbtab  & cm.autoid
    response.write vbcrlf
%>    DataType:<%
    response.write vbtab  & cm.datatype
    response.write vbcrlf
%>    Nullable:<%
    response.write vbtab  & cm.nullable
    response.write vbcrlf
%>    Length:<%
    response.write vbtab  & cm.length
    response.write vbcrlf
%>    Precision:<%
    response.write vbtab  & cm.Precision
    response.write vbcrlf
%>    Scale:<%
    response.write vbtab  & cm.NumScale
    response.write vbcrlf
%>    Description:<%
    response.write vbtab  & cm.Description
    response.write vbcrlf
next 
%>

generate by cpdedg <%= Now %><%
filepath = app.path & “\test.txt”

set fso = createobject(“Scripting.FileSystemObject“)
Set ts = fso.CreateTextFile(filepath, True, True)
ts.Write CEG_RESULT
ts.Close

if iif (msgbox (“file has saved to “ & filepath & vbcrlf _
    & “do you want to delete this file?“,vbQuestion +vbYesNo )=vbYes ,true,false) then
    fso.DeleteFile filepath ,True
end if

‘ you must use ’start with all tables’ to fill all tables of schema
b=true
for each tbl in schema.Tables.Items
    if tbl.columns.count = 0 then
        b= false
    end if
next

if b then
    for each tbl in schema.Tables.Items
        response.write “table name:“ & vbtab & tbl.name     & vbcrlf
        response.write “column count:“ & vbtab & tbl.columns.count & vbcrlf
    next
end if
%>

然后这是一个生成结果：

This is a example script template.
You can write script as same as what’s in ASP.

Table:Area
Comment:
Column count:4
========Traverse all column‘s property=========
column:    Code
    Primary Key:    True
    Auto Identity:    False
    DataType:    varchar
    Nullable:    False
    Length:    10
    Precision:   
    Scale:   
    Description:    编号
column:    Name
    Primary Key:    False
    Auto Identity:    False
    DataType:    varchar
    Nullable:    False
    Length:    50
    Precision:   
    Scale:   
    Description:    名称
column:    Remark
    Primary Key:    False
    Auto Identity:    False
    DataType:    varchar
    Nullable:    True
    Length:    255 Precision: Scale: Description: 说明column: rowguid Primary Key: False
    Auto Identity:    False
    DataType:    uniqueidentifier
    Nullable:    False
    Length:   
    Precision:   
    Scale:   
    Description:  

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