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    <p>Don't forget to set the value of the <code>Bar</code> property in your model object when you don't want to store 0. When you create a new object and call <code>SaveChanges</code> an INSERT command is sent to the database which contains the value of <strong>all</strong> your model properties which are mapped to the DB table. An <code>int</code> property in a class has always a value and you have set this value to 0 - namely by calling the object's constructor.</p> <p>EF doesn't sent only one half of the object to the database, that's an essential point of an Object-Relational-Mapper. Of course by submitting a raw SQL INSERT command you can set only one half of a table row's column values and you would get an exception if you don't set a value for the <code>Bar</code> column. But when you use an ORM you don't submit INSERT commands but you store new objects.</p> <p>What is exactly the problem? If not having a value for <code>Bar</code> is valid the column should be nullable and the property <code>int?</code>. If it must have a value but not the value 0 then it's a matter of setting <code>Bar</code> to 1 or something in the object's constructor or apply proper validation before you save an object.</p> <p>The kind of exception you would like to have is impossible and makes no sense in my opinion because it's impossible <strong>not</strong> to set a value in the INSERT command EF will submit when storing the object</p>
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    1. COThanks, sure setting the value in code is fine but thats not the problem. Imagine a scenario with 20+ different applications writing data to the database. The DB constraint says "you have to supply a valid value for this column". It would be nice to have this constraint respected by the ORM as I cant gaurantee that every app is implemented correctly. This type of feature has been around for 20+ years. If the field is not dirty, dont write it to the DB or throw. Dont just write arbitrary defaults from the framework to the DB.
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    2. CO@bic: The constraint is respected in the sense that all properties for a *new* object are dirty and for updates only changed columns are sent to DB in an update command. The type of constraint check was only necessary because in a relational DB you *can* set individual columns when creating a new row. In an ORM (and also OO databases) you can't, thus the constraint check isn't necessary. Maybe it's an example of an "object-relational impedance mismatch": a simpe data type with no default value doesn't exist on the "O" side like a column with "no default" on the "R" side.
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    3. CO@bic: Another point: Consider you work with POCOs. An object is "somewhere" created, outside of the context, for instance in another assembly or it even comes from any kind of remote service, and the developer at the other side of the wire has explicitely set `Bar` to 0 because it's the valid value he wants to store. How could EF recognize if this is a "default value" created in the object constructor or if it has been set explicitely in code? It can't I think. This kind of detection if the value has been set explicitely or not is impossible, at least with POCOs.
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