Using the Caché Managed Provider for .NET - InterSystems ...

Using Proxy Objects5.3 Using Proxy ObjectsCaché proxy objects can be used to perform most of the standard operations on instances in a database.This section describes how to open and read an instance, how to create or delete instances, and howto alter and save existing instances.5.3.1 Opening and Reading ObjectsUse the OpenId() method to access an instance by ID (instances can also be accessed through SQLqueries, as discussed later in Using Caché Queries). OpenId() is a static class method, qualified withthe type name rather than an instance name:Sample.Person person = Sample.Person.OpenId(CacheConnect, "1");Once the object has been instantiated, you can use standard dot notation to read and write the personinformation:string Name = person.Namestring ID = person.Id();person.Home.City = "Smallville";person.Home.State = "MN";In this example, person.Home is actually an embedded Sample.Address object. It is automaticallycreated or destroyed along with the Sample.Person object.For a working example, see the Proxy_1_ReadObject() method in the bookdemos sample program(see The Caché .NET Sample Programs).5.3.2 Creating and Saving ObjectsCaché proxy object constructors use information in a CacheConnection object to create a link betweenthe proxy object and a corresponding object on the Caché server:Sample.Person person = new Sample.Person(CacheConnect);person.Name = "Luthor, Lexus A.";person.SSN = "999-45-6789";Use the Save() method to create a persistent instance in the database. Once the instance has been saved,the Id() method can be used to get the newly generated ID number:CacheStatus sc = person.Save();Display.WriteLine("Save status: " + sc.IsOK.ToString());string ID = person.Id();Display.WriteLine("Saved id: " + person.Id());The ExistsId() class method can be used to test whether or not an instance exists in the database:Using the Caché Managed Provider for .NET 37