Quick & Easy OR Mapping with Euss

Creating A Visual Studio .Net Solution

You can download the source code for this sample here.

Open Visual Studio and create a blank solution named EussDemo by clicking on the following menu items:

File
New Project
Other Project Types
Visual Studio Solutions
Blank Solution

Generating The Domain Model Classes

The easiest way to store objects using Euss is to use the code generation tools shipped with it. Code generation is based on XML file containing a description of the classes to generate.

There are two different ways to generate the classes with Euss:

Using Visual Studio .Net
Using a command line utility named domain.exe

Code Generation within Visual Studio .Net

Add a new Class Library named EussDemo.Domain to the solution by clicking on the following menu items:

File
Add
New Project
Visual C#
Class Library

Remove the unnecessary Class1.cs file

Add a reference to Euss by clicking on the following menu items:

Project
Add Reference
Evaluant Universal Storage Services for .Net 2.0

Add a new Euss model file named EussDemo.Domain.xml by clicking on the following menu items:

Project
Add New Item
Euss Domain Model File

Type the following content and save the file.

<?xml version="1.0" encoding="utf-8" ?>
<?evaluant-application progid="EUSS.GenerationModel"?>
<Model xmlns="http://euss.evaluant.com/schemas/GenerationModel.xsd">
  <Package name="EussDemo.Domain">

    <Class name="Customer">
      <Property name="Name" type="System.String" />
    </Class>

    <Class name="Order">
      <Property name="Amount" type="System.Int32" />
    </Class>

    <Relationship type="composition">
      <Parent name="Customer" role="Customer" multiplicity="1" />
      <Child name="Order" role="Orders" multiplicity="*" />
    </Relationship>
    
  </Package>
</Model>

The code generation process is transparently launched as soon as you save this file.

Generating The Mapping File

A mapping file is an XML file containing the description of the links between the objects you want to store and a database schema where you will put those objects.

Mapping File Generation With The Command Line Utility

Open an Euss Command Prompt:

Start
Programs
Euss
Euss Command Prompt

Type this command:

mapping.exe /model:"c:\temp\EussDemo\EussDemo.Domain\EussDemo.Domain.xml" /out:"c:\temp\EussDemo\EussDemo.Domain\EussDemo.Domain.eum.xml"

A mapping file will be created in the same folder as the domain model file.

NB: If an error message is displayed, please check the location of the file.

The content of the file should be like this:

<?xml version="1.0" encoding="utf-8"?>
<Mapping xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Entity type="EussDemo:Domain:Customer" table="Customer">
    <Id field="CustomerId">
      <Generator name="guid" />
    </Id>
    <Attribute name="Name" field="Name" db-type="String" size="50" />
    <Reference name="Orders" entityChild="EussDemo:Domain:Order">
      <Rule parentField="CustomerId" childTable="Order" 
            childField="FK_CustomerId" />
    </Reference>
  </Entity>
  <Entity type="EussDemo:Domain:Order" table="Order">
    <Id field="OrderId">
      <Generator name="guid" />
    </Id>
    <Attribute name="Amount" field="Amount" db-type="Int32" />
  </Entity>
</Mapping>

Creating A Console Application

Add a new Console Application named EussDemo.Test to the solution by clicking on the following menu items:

File
Add
New Project
Visual C#
Console Application

Add a reference to Euss by clicking on the following menu items:

Project
Add Reference
Evaluant Universal Storage Services for .Net 2.0

Add a reference to EussDemo.Domain by clicking on the following menu items:

Project
Add Reference
Project
EussDemo.Domain

Add a new configuration file named engines.config by clicking on the following menu items:

Project
Add New Item
Euss Engine Configuration File

The sample content is based on an XML Provider. To be able to persist the data in a SQL Server database we have to change its content with this one:

<?xml version="1.0" encoding="utf-8"?>
<PersistenceEngines 
  xmlns="http://euss.evaluant.com/schemas/EngineConfiguration.xsd" 
  DefaultEngine="Sql">

  <PersistenceEngine Name="Sql" 
      Factory=" Evaluant.Uss.SqlMapper.SqlMapperProvider">
    <ConnectionString>Server=.;DataBase=uss;UID=sa;PWD=</ConnectionString>
    <Dialect>Evaluant.Uss.SqlMapper.MsSqlDialect</Dialect>
    <Driver>Evaluant.Uss.SqlMapper.MsSqlDriver</Driver>
    <MappingFileName>~/EussDemo.Domain.eum.xml</MappingFileName>
    <Metadata Type="model">~/EussDemo.Domain.xml</Metadata>
  </PersistenceEngine>

</PersistenceEngines>

NB: You have to change the connection string and create the corresponding database in SQL Server.

The configuration tells the application to load the metadata and the mapping from the file we created in the EussDemo.Domain project. We then have to copy those file in the same folder as the compiled application. To do it, select those files in Visual Studio .Net, and in the Properties window select Copy If Newer in Copy to Output Directory. Repeat this operation with engines.config.

Copy this content in Program.cs and run the application:

using System;
using System.Collections.Generic;
using System.Text;

using EussDemo.Domain;
using Evaluant.Uss.ObjectContext;

namespace EussDemo.Test
{
    class Program
    {
        static void Main(string[] args)
        {
            ObjectService os = new ObjectService("engines.config");
            ObjectContext oc = os.CreateObjectContext();
            oc.InitializeRepository(); // Creates all the tables in the database

            Customer c = new Customer();
            c.Name = "Eric";

            Order o1 = new Order();
            o1.Amount = 10;

            Order o2 = new Order();
            o2.Amount = 20;

            c.Orders.Add(o1);
            c.Orders.Add(o2);

            oc.BeginTransaction();
            oc.Serialize(c);
            oc.CommitTransaction();

            IList<Order> myOrders = 
                oc.Load<Order>(typeof(Customer), "[Name = 'Eric'].Orders");

            foreach (Order o in myOrders)
                Console.WriteLine(o.Amount);
        }
    }
}

In the database you can see that all the objects were persisted in specific tables: