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I'm working on a custom entity framework provider and I need to add support for default column values for this provider. When the user uses the entity framework wizard and selects a table that includes columns with default values, those default values are not being populated into the entity designer.

I'm a little lost on where exactly this population should take place. I believe the appropriate place would be in the GetEdmType method override of DbXmlEnabledProviderManifest but I just don't see how to set the default value, if this is the correct place.

Anybody has experience writing EF providers that support default values for table columns? How do you implement this?

Julio Casal
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I am a bit late to the party but DbXmlEnabledProviderManifest is not the right place for adding default values. The provider manifest describes capabilities of the database engine itself and is specific (and general) to this database engine and not to a given database and/or table. The default value in the provider manifest tells EF what value to use for the given column property if one is not provided by the user (e.g. if the user user does not specify scale or precision for a decimal column the value from provider manifest will be used for scale and/or precision used for this column). If you want just to insert a default value for a property the easiest way is to set the property that corresponds to the column on your entity to this value in the constructor. This way the user can always set it to a different value but if s/he does not the default value will be sent to the database. For some corner case scenarios where some of the columns in the database do not have corresponding properties on entities you can use DefaultValue attribute on the Property element in SSDL which will be inserted to the database when you add a row. This is especially useful if those properties are not nullable since without telling EF what value should be inserted EF would try inserting null which would obviously fail for non-nullable columns.

Pawel
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