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POStore objects with common base class in database
 

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    <p>Let's say i have a common base class/interface</p> <pre><code> interface ICommand { void Execute(); } </code></pre> <p>Then there are a few commands inheriting from this interface.</p> <pre><code> class CommandA : ICommand { int x; int y; public CommandA(int x, int y) { ... } public void Execute () { ... } } class CommandB : ICommand { string name; public CommandB(string name) { ... } public void Execute () { ... } } </code></pre> <p>Now i want to store these commands in a database, with a common method, and then later load all of them from the DB into a <code>List&lt;ICommand&gt;</code> and execute the Execute-method of them.</p> <p>Right now I just have one table in the DB called commands and here i store a string serialization of the object. Basically the columns in the table are: <code>id|commandType|commaSeparatedListOfParameters</code>. While this is very easy and works good for <em>loading all</em> commands, I can't <em>query</em> the commands easily without using substring and other obscure methods. I would like to have an easy way of <code>SELECT id,x,y FROM commandA_commands WHERE x=...</code> and at the same time have a generic way of loading all commands from the commands-table (i guess this would be some kind of UNION/JOIN of commandA_commands, commandB_commands, etc). </p> <p>It is important that not much manual fiddling in the DB, or manual creation of serialize/parse-methods, is required to add a new command. I have tons of them and new ones are added and removed all the time. I don't mind creating a command+table+query generation tool though if this would be required for the best solution.</p> <p>The best i can think of myself is a common table like <code>id|commandType|param1|param2|param3|etc..</code> which isn't much better (actually worse?) than my current solution as many commands are going to need null parameters and the datatype will vary so i have to resort to common string conversion again and size each field big enough for the largest command.</p> <p>The database is SQL Server 2008</p> <p><strong>Edit:</strong> Found similar question here <a href="https://stackoverflow.com/questions/3413459/designing-sql-database-to-represent-oo-class-hierarchy">Designing SQL database to represent OO class hierarchy</a></p>
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