Hi,
I'm new to NHibernate so may be trying to do the impossible. Any advice as to how to accomplish my goal with any solution would be very much appreciated.
I have two versions of an almost identical database. Below I have created an Example table to demonstrate the basic differences, namely the ID column has changed from an Integer Identity to a GUID and various properties have been updated, in the Example archived has been replaced with readOnly and hidden:
Legacy version:
Code:
CREATE TABLE Example
(
--Data Identity (maps to DbId in the example code)
Id int IDENTITY PRIMARY KEY,
--Example columns
SomeValue varchar(50),
AnotherValue int,
--Data Properties
Archived bit
)
New version:
Code:
CREATE TABLE Example
(
--Data Identity (maps to DbId in the example code)
Id uniqueidentifier PRIMARY KEY,
--Example columns
SomeValue varchar(50),
AnotherValue int,
--Data Properties
ReadOnly bit,
Hidden bit
)
I want to use NHibernate to connect to one or other of these database versions. I would like to be able to tell the application which version to use through settings in a configuration file.
My initial plan was to create a common interface for the business logic and use an IoC container such as Unity to swap between the relevant concrete classes in the configuration file.
Can anyone advise if this is possible and if so how to create the relevant NHibernate mapping files?
Alternatively, can anyone suggest any solution to the problem using any other methods or tools (commercial or open source)?
Here is an example of the business logic I created to test the Unity approach:
Code:
public interface IDataIdentity
{
object Id { get; }
}
public class LegacyDataIdentity : IDataIdentity
{
public virtual long DbId { get; set; }
public object Id
{
get { return DbId; }
}
}
public class NewDataIdentity : IDataIdentity
{
public virtual Guid DbId { get; set; }
public object Id
{
get { return DbId; }
}
}
public interface IDataProperties
{
bool ReadOnly { get; set; }
bool Hidden { get; set; }
}
public class LegacyDataProperties : IDataProperties
{
public virtual bool Archived { get; set; }
public bool ReadOnly
{
get { return Archived; }
set { Archived = value; }
}
public bool Hidden
{
get { return Archived; }
set { Archived = value; }
}
}
public class NewDataProperties : IDataProperties
{
public virtual bool ReadOnly { get; set; }
public virtual bool Hidden { get; set; }
}
public class DataItem
{
public DataItem(IDataIdentity dataIdentity, IDataProperties dataProperties)
{
DataIdentity = dataIdentity;
DataProperties = dataProperties;
}
public IDataIdentity DataIdentity { get; set; }
public IDataProperties DataProperties { get; set; }
}
public class Example : DataItem
{
public Example(IDataIdentity dataIdentity, IDataProperties dataProperties)
: base(dataIdentity, dataProperties)
{
}
public virtual string SomeValue { get; set; }
public virtual int AnotherValue { get; set; }
}
Many thanks,
Paul
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