Retrieve Primary Key Fieldnames

[Nikolai Hellwig]

Hi,

Let's say i have a class generated by the reverse mapping tool named "Land".

How could i figure out in code which fields belong to the primary key, without typing the name of the table?

I'd like to write a generic method, so i don't want to change it everytime a new table is added to the project.

ex.    Input = class ie. type, Output = primary key fieldnames (propertynames in case of c#)

thanks

Nikolai Hellwig

CHW Software GmbH

[Nikolai Hellwig]

sorry,

i found a solution by myself. I have to use: 

IPersistentTypeDescriptor desc = scope.PersistentMetaData.GetPersistentTypeDescriptor(typeof(Land));

thanks

[PetarP]

Hello Nikolai Hellwig,

The easiest way would be to traverse our metadata tree and extract the primary keys from there. Here is a sample method that can be used to extract the primary keys for each of your persistent types:

static void Main(string[] args)
       {
           NorthwindEntityDiagrams db = new NorthwindEntityDiagrams();
           List<string> primaryKeys = ExtractPrimaryKeysForType(typeof(OrderDetail), db);
           foreach (string primaryKey in primaryKeys)
           {
               Console.WriteLine(primaryKey);
           }

       }
       private static List<string> ExtractPrimaryKeysForType(Type type, OpenAccessContext db)
       {
           MetaPersistentType persistentType = db.Metadata.PersistentTypes.Where(c => c.FullName == type.FullName).First(); //Selects the Persistent type from the metadata
           return persistentType.Members.Where(c => (c is MetaPrimitiveMember) && (c as MetaPrimitiveMember).IsIdentity == true).Select(c => c.PropertyName).ToList(); //Retrieves a list of the primary keys
       }

All the best,
Petar
the Telerik team

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