Distributed keys / Inheritance
От | Michael Glaesemann |
---|---|
Тема | Distributed keys / Inheritance |
Дата | |
Msg-id | B52AD44C-3646-11D8-97F0-000A95C88220@myrealbox.com обсуждение исходный текст |
Список | pgsql-hackers |
Here's Tom Lane's response to my original post on pgsql-sql: > This seems to have considerable overlap with the problem of indexing > inheritance hierarchies (so that constraints on tables with children > would work as people expect). It may be that it's sufficient to solve > it for inheritance cases, and not try to support the generic case of > constraints applied across arbitrary sets of tables. ISTM that the > latter could introduce a bunch of extra definitional and practical > issues beyond what you'd have to solve to do the former. > > You're discussing it on the wrong list though --- try -hackers. Hadn't thought of distributed keys being related to inheritance, though now I can see how one might apply inheritance to the situations I mentioned above. Is this what you were thinking, Tom? Case 1: employees (id, name) schools (name, location) teachers (id, name, school_name)where (id, name) inherits from employees and school_name references schools(name) subs (id, name) inherits from employees managers (id, name, school_name)where (id, name) inherits from employees and school_name references schools(name) Case 3 comments (comment_id, comment) employees(id, name) comments_nonemployees (comment_id, comment, name)where (id, comment) inherits from comments comments_employees (comment_id, comment, employee_id)where (comment_id,comment) inherits from comments, employee_id references employees(id) I don't know very much about inheritance in PostgreSQL, so I'm doing a bit of reading via Google. If anyone has recommendations on good sources re: inheritance in PostgreSQL, I'd be thankful. Regards, Michael Glaesemann grzm myrealbox com
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