/// <summary>Limits the query to unique results.</summary>
/// <returns>
/// A new <see cref="T:System.Data.Entity.Core.Objects.ObjectQuery`1" /> instance that is equivalent to the original instance with SELECT DISTINCT applied.
/// </returns>
public ObjectQuery <T> Distinct()
{
if (ObjectQuery <T> .IsLinqQuery((ObjectQuery)this))
{
return((ObjectQuery <T>) this.Distinct <T>());
}
return(new ObjectQuery <T>(EntitySqlQueryBuilder.Distinct(this.QueryState)));
}
/// <summary>
/// This query-builder method creates a new query whose results are all of
/// the results of this query, plus all of the results of the other query,
/// without duplicates (i.e., results are unique).
/// </summary>
/// <param name="query"> A query representing the results to add. </param>
/// <returns> a new ObjectQuery instance. </returns>
/// <exception cref="T:System.ArgumentNullException">If the query parameter is null.</exception>
public ObjectQuery <T> Union(ObjectQuery <T> query)
{
Check.NotNull <ObjectQuery <T> >(query, nameof(query));
if (ObjectQuery <T> .IsLinqQuery((ObjectQuery)this) || ObjectQuery <T> .IsLinqQuery((ObjectQuery)query))
{
return((ObjectQuery <T>) this.Union <T>((IEnumerable <T>)query));
}
return(new ObjectQuery <T>(EntitySqlQueryBuilder.Union(this.QueryState, query.QueryState)));
}
/// <summary>Limits the query to only results of a specific type.</summary>
/// <returns>
/// A new <see cref="T:System.Data.Entity.Core.Objects.ObjectQuery`1" /> instance that is equivalent to the original instance with OFTYPE applied.
/// </returns>
/// <typeparam name="TResultType">
/// The type of the <see cref="T:System.Data.Entity.Core.Objects.ObjectResult`1" /> returned when the query is executed with the applied filter.
/// </typeparam>
/// <exception cref="T:System.Data.Entity.Core.EntitySqlException">The type specified is not valid.</exception>
public ObjectQuery <TResultType> OfType <TResultType>()
{
if (ObjectQuery <T> .IsLinqQuery((ObjectQuery)this))
{
return((ObjectQuery <TResultType>)Queryable.OfType <TResultType>(this));
}
this.QueryState.ObjectContext.MetadataWorkspace.ImplicitLoadAssemblyForType(typeof(TResultType), Assembly.GetCallingAssembly());
Type type1 = typeof(TResultType);
EdmType type2;
if (!this.QueryState.ObjectContext.MetadataWorkspace.GetItemCollection(DataSpace.OSpace).TryGetType(type1.Name, type1.NestingNamespace() ?? string.Empty, out type2) || !Helper.IsEntityType(type2) && !Helper.IsComplexType(type2))
{
throw new EntitySqlException(Strings.ObjectQuery_QueryBuilder_InvalidResultType((object)typeof(TResultType).FullName));
}
return(new ObjectQuery <TResultType>(EntitySqlQueryBuilder.OfType(this.QueryState, type2, type1)));
}