Is
employee really a subclass of person, or is employee just a role that a person
has? Here is a blurb from Barney Boisvert's blog on the
topic:
http://www.barneyb.com/blog/archives/000310.jsp
is-a, has-a - These are the two core types of relationships between objects. Is-a relationships are inheritance, where you say "a Corvette is a Car is a Vehicle". Has-a relationhips are composition, where you say "a User has a Role which has some Responsibilities". Wherever there is ambiguity between which type of relationship to use, the natural instinct is usually to go with is-a, but the proper solution is usually to go with has-a. ; )
is-a, has-a - These are the two core types of relationships between objects. Is-a relationships are inheritance, where you say "a Corvette is a Car is a Vehicle". Has-a relationhips are composition, where you say "a User has a Role which has some Responsibilities". Wherever there is ambiguity between which type of relationship to use, the natural instinct is usually to go with is-a, but the proper solution is usually to go with has-a. ; )
---------------------------------------------------------------Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Samson
Sent: Tuesday, February 14, 2006 6:20 AM
To: CFC DEV
Subject: [CFCDev] DAO InheritanceI have a base object 'person' for which I have defined both a personObj to hold information and a personDAO to handle persistance. My person DAO has a getById() function which takes a uuid and returns a cfc of type personObj.I now want a new object 'employee' so I create an employeeObj which extends person, and to handle the persistance I create a employeeDAO which extends personDAO. employee DAO also has a getById() function which takes a uuid and should return a cfc of type employeeObj.My employeeDAO.getById() function is causing me problems. I am trying to call super.getById() but this returns an object of type personObj rather than employeeObj.How can I leverage the DAO code I have written in the parent object?John
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