public MergePolicy MergePolicy {get; set;}

public void CreateCodedDomainSnippet(Geodatabase geodatabase)
{
  // Create a CodedValueDomain description for water pipes
  CodedValueDomainDescription codedValueDomainDescription = new CodedValueDomainDescription("WaterPipeTypes", FieldType.String,
    new SortedList<object, string> { { "C_1", "Copper" }, { "S_2", "Steel" } })
  {
    SplitPolicy = SplitPolicy.Duplicate,
    MergePolicy = MergePolicy.DefaultValue
  };

  SchemaBuilder schemaBuilder = new SchemaBuilder(geodatabase);

  // Create a coded value domain 
  CodedValueDomainToken codedValueDomainToken = schemaBuilder.Create(codedValueDomainDescription);
  schemaBuilder.Build();
}