Question

如果您可以使用方法链接来获得结果，例如下面的行

cReportcard.student("doe").Metric("math").score

如何将物业带回连锁店？

我有一系列主题的自定义类（例如，数学，语言艺术，pe ...）。自定义课程有学生，分数，老师，课堂，时期。

我怎么能

cReportcard.student("doe").Metric("math").score=0.96

并将值链向后转到原始类集合？

我想这就像＆＃34;父母＆＃34; Worksheet类的属性。我只是想不出怎么做。

到目前为止，我设计了一个包含4个表（学生，公制，成绩，期间）的表格方案

Student(ID [pk], NAME, DOB)
Metric (ID [pk], NAME)
Period (ID [pk], METRIC_ID [fk], GRADE_LEVEL, START_TIME, LENGTH, CLASS_RM, TEACHER_ID [fk])
Grade (ID [pk], PERIOD_END_DATE, PERIOD_ID [fk], STUDENT_ID [fk], METRIC_SCORE

）

Answer 1

我认为您可能需要花一点时间来定义确切的用例，以确保这些表能够快速执行您需要的任何操作。但假设这是最终的结构，我会设计这样的类：

clsGrade：

'It would be better to have them all private and provide get/set properties
Private ID As Long
Public Student As clsStudent
Public Period As clsPeriod
Public Period_End_Date As Date
Public Metric_Score As Long

'This assumes that, per your example, the only fields necessary to find a "grade" are student name and metric
Public Sub Load(studentName As String, Metric As String)
    Dim rs As Recordset
    'SQL query to get the grade for a particular student/metric

    Set Student = New clsStudent
    Student.Load rs!STUDENT_ID

    Set Period = New clsPeriod
    Period.Load rs!PERIOD_ID

End Sub

Public Sub Save()
    'SQL query to save the grade

    'You would have to decide whether or not this cascades and saves the Student/Period/Metric info as well.
    Student.Save
    Period.Save
End Sub

clsMetric：

'It would be better to have them all private and provide get/set properties
Private ID As Long
Public Name As String

Public Sub Load(ID As Long)
    'SQL to load a metric by ID
End Sub

Public Sub Save()
    'SQL to save the metric
End Sub

clsPeriod：

'It would be better to have them all private and provide get/set properties
Private ID As Long
Public Metric As clsMetric
Public Grade_Level As Long
Public Start_Time As Date
Public Length As Date
Public Class_Rm As String
Public Teacher_ID As Long

Public Sub Load(ID As Long)
    Dim rs As Recordset
    'SQL to load a period by ID

    'Also load the child metric
    Set Metric = New clsMetric
    Metric.Load rs!METRIC_ID

End Sub

Public Sub Save()
    'SQL to save the period

    'Also save the child metric
    Metric.Save
End Sub

clsStudent：

'It would be better to have them all private and provide get/set properties
Private ID As Long
Public Name As String
Public DOB As Date

Public Sub Load(ID As Long)
    'SQL to load a student by ID
End Sub

Public Sub Save()
    'SQL to save the student
End Sub

然后你可以这样使用它们：

Public Sub Main()
    Dim grade As clsGrade
    Set grade = New clsGrade
    grade.Load "doe", "math"
    grade.Metric_Score = 0.96
    grade.Save
End Sub

如果你想简化它并获得想象力，你可以做Get / Let属性并添加一个＆＃34;脏＆＃34;对每个类进行控制以跟踪自加载以来是否有任何更改。这样你就不会保存那些没有改变的信息。

VBA物业链？

1 个答案: