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    <p>I don't really understand how you want to work stateless, but update only changed properties. It will never work when stateless, since you will need a before-after comparison, or anything else to track changes (like events on property setters). Special "virgin" values are not a good solution, since I think your user wants to see the actual IntField value.</p> <p>Also make your database consistent with your application data - if you have standard, not-nullable int values, make the DB column <em>int not null default 0</em>! It is really a pain to have a database value which can't be represented by the program, so that the software "magically" turns DB null into 0. If you have a not-nullable int in your application, you can't distinguish between DB null and zero, or you have to add a property like <em>bool IsIntFieldNull</em> (no good!). </p> <p>To reference a common Object-relational mapper, NHibernate: it has an option called "dynamic-update" where only changed properties/columns are updated. This requires, however, a before-after check and stateful sessions, and there's debate on whether it helps performance, since sending the same DB query every time (with different parameter values) is better than sending multiple different queries - opposed to unneccessary updates and network load. By default, NHibernate updates the whole row, after checking if any change has been done. If you only have ID, StringField and IntField, dynamic-update instead of full-row update might in fact be a good solution.</p> <p>Mapping nullable DB columns to not-nullable application data types, such as int, is a common mistake when implementing NHibernate, since it creates self-changing DAL objects.</p> <p>However, when working with ORM or writing your own DAL, make sure you have proper database knowledge!</p>
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    1. USErik Hart
    1. USErik Hart
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    1. COWeb client has the knowledge about which properties are changed. So actually the problem is how Web client passes the change down through the application server - BLL layer - DAL layer. We internally had discussed to create a base class to capture the setter method (exactly the sampe way as Hatcyl mentioned), but unfortunately not passed for a) it violates POCO pattern, b) most serialization tools make uses of setter methods.
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      1. USWeiquan Zhang
    2. COI were thinking about an approach that: create a Query-like object, which is used to record which properties are changed. It was still not a good solution. When application built on this mechanism, there would be lots of hard code, and ORM pattern would fail.
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