I\'ve got a Patient entity (storing up-to-date information about a patient) and a TreatmentPlanPatient entity (a copy of a patient\'s date as it was when the \"treatment plan\", another entity not rel
I\'ve created a database using the EF4 model-first approach. In my model, there\'s an N-to-M relationship between two entities:
What is the difference between Unidirectional and Bidirectional associations? Since the table generated in the db are all the same,so the only difference I found is that each side of the bidiretional
I have a table structure that uses a link table to relate Jobs to People, the link table contains data information for how long a person was at a particular job.
I have an model PointOfContact which has_many Systems. From the Systems side I want to identify the PointOfContact as either the technical_manager or p开发者_JS百科roject_manager (or both). While stil
I\'m having a problem getting my data model to work correctly. I have the following models and sub models.
I\'m stuck - I\'m building an accounting app in rails, and have a model where a customer will have multiple invoices as well as multiple payments (related to those invoices)
I have this ER model Message 0..1 <--> 0..1 MessageDetail PK:ID_MESSAGEPK: ID_DETA开发者_Python百科IL
I kept getting this error in my Rails app after upgrading to Rails 3. >> u.sent_messages NoMethodError: undefined method `attribute_condition\' for #Class:0x105523f18
Hopefully I don\'t get flamed for this one too bad - I\'ve tried my very hardest to find an answer to no avail.
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