Question

I have an edmx file and I changed a table in my database. I know that there is an “Update Model from database” wizard, however in many cases this is useless.

For example if I change a field from non null to nullable or if I remove fields the update model does not reflect the changes. I have had to remove the entity and add it back in to get the changes to appear in my model.

Per the following question:
How do I propagate database changes to my .edmx file?

One of the answers seems to say the same thing, that you need to remove the entity and add it back in.

Is this the definitive answer or is there a better way to do this?

Answer 1

An important first step is to understand exactly what happens when you use the update model wizard.

From the MSDN Library:

The ADO.NET Entity Data Model Designer (Entity Designer) uses the Update Model Wizard to update an .edmx file from changes made to the database. The Update Model Wizard overwrites the storage model as part of this process. The Update Model Wizard also makes some changes to the conceptual model and mappings, but it only makes these changes when objects are added to the database. For example, new entity types are added to the conceptual model when tables are added to the database, and new properties are added to entity types when columns are added to a table. For details about what changes are made to the .edmx file, see Changes Made to an .edmx File by the Update Model Wizard.

When you updated the database using the update model wizard, it updated the storage model in the .edmx file and not the conceptual model. When changes are made to the definition of existing objects, only the storage model is updated; the conceptual model is not updated. For a complete description of changes that are made by the update model wizard, please see the “Changes Made to an .edmx File by the Update Model Wizard” link above.

Here are some options on how to update objects that are not updated by the update model wizard (based on your scenario where a the column definition was altered):

1. Use the update model wizard (to update the storage model), open the .edmx file using the designer (default), find the desired scalar property and edit the desired properties in the Properties windows.
2. Use the update model wizard (to update the storage model), open the .edmx file using the XML editor, find the desired property in the CSDL (conceptual model) section and change the desired attributes. This is basically the same as option 1, but you’re editing the XML directly (a find and replace might be useful here).
3. From the Model Browser, delete the desired entity from the Entity Types section of the conceptual model and the desired table from the Tables / Views section of the storage model. Then use the update model wizard to add it back.

The best option would depend on the given scenario. For example, if you just altered the definition of one column, then option 1 is likely you best choice. If you altered the definition of a number of columns in a single table, then option 3 might be your best choice. If you altered a column that is used across a number of tables (such as a primary / foreign key), then editing the .edmx XML directly might be your best option.