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I've decided to test and try DougM approach to handle it with a Java String and no relation on other objects, so in that way I still have the referecne and I still have some aditional checks to implement to avoid the loss of referecne from other objects.


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I would avoid any ad-hoc, on-demand, database replication. Ideally you want a single consistent, logical user database across all of your nodes, for disaster purposes. @Wardy's recommendation of a service bus is a good one. I won't discuss different cluster architectures, but will address the issue of network bandwidth and transaction volume. With high ...


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Sounds like a typical use for a service bus based solution. I solved exactly this problem but for keeping running servers live and interconnected and in sync with each other in my MMO server framework. The simple answer is "don't try and sync the data once its in the database use an event and handle it in multiple locations". It's basically like taking ...


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There are better patterns for describing hierarchical data structures for example the nested set model. (In your case you probably need a tree identifier because you want to describe multiple trees.) About the naming. If you are not sure you describe a parent/child relationship, then it is better to describe a graph with nodes and links. In your case the ...


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The greatest complexity for query builders comes out of trying to handle the scope of ANDs an ORs. If you can handle these elegantly, your model can be simpler. I recommend having two sorts of predicates: Your vanilla predicate: value1 operator value2. Your compound predicated (or what we might call "implied parentheses"). The whole compound is tagged ...


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Usually, translations are not something that change at run time. They are set before the server starts and remain static as long as the server is running. And what you are showing does not require any kind of complex queries to operate. So I would not put the data you show us in a database system like MySQL but in files named according to a sensible naming ...


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My general answer is that use any databases that you think would improve your service. You wrote: I'm just wondering, after building the initial product, if your product is likely to grow and change, is it a good idea to stick with mongoDb? Yes, especially if the schema is going to change, MongoDB is easier to maintain in this case. In a way, it is ...


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I think it is a good idea to take query performance into consideration early in the design phase, but at some point, your database has to hold the data required by your application. Even if your table design isn't optimal, you can change it later (easier said than done), improve indexing, cache query results (different databases offer their own solutions), ...


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I hacked a basic example with Mysql Workbench in 5 minutes You can have different methods to keep track of borrowed and returned, I showed an example with borrow_history to keep history and you can manage if library_items are out or not via "borrowed_until" field. You can also track how many books a student took out via "borrowed", that you can += 1 upon ...


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There are 2 entities. One is admin. The task of admin is to define slots for appointments which will be taken by applicants. admin sounds more like an user that an entity. Of course, user may be an entity (or not if your model does not incorporate authorization information). I see many nouns there : "The task of admin(user) is to define slots for ...


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Is it really a big performance issue to make multiple tables with unique columns. I have heard indexing columns help quite a lot? This depends on the DB system. Almost any relational DB system I know of automatically will add an index for primary keys. Some DB systems also add indexes automatically for each FK constraint, some others do not. For foreign ...


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DB systems are fast. Unless you are doing something like web portal for many schools to use your software on the same platform, you should usually have no trouble with a regular HW (provided that you generate the queries in a somewhat sane manner). That said, if you still have doubts it is not that difficult to create an script that will populate your ...


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1 -- should not be a problem until you hit millions of rows. Generally speaking you should start out with a clean "logical" schema and change it when and if you hit a performance problem. 2 -- Views are just "canned sql" querying a view is no different from running the underlying SQL. There are good reasons to use views but performance is not one of them. ...



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