LINQ Examples 6

Projection operators

[Description("This samples uses SELECT to get all Customers as Entity Objects.")]
public void LinqToEntities11() {
  var query = from c in _em1.Customers
              select c;
  Assert.IsTrue(query.Count() == 91);
}

[Description("This samples uses SELECT to get all Customer Contact Names as Strings.")]
public void LinqToEntities12() {
  var query = from c in _em1.Customers
              orderby c.ContactName
              select c.ContactName;
  var r = query.ToList();
  Assert.IsTrue(r.First() == "Alejandra Camino");
}

[Description("This samples uses SELECT to get all Customer Contact Names as an anonoymous type.")]
public void LinqToEntities13() {
  var query = from c in _em1.Customers
              orderby c.CompanyName
              select new { c.ContactName };

  var r = query.ToList();
  Assert.IsTrue(r.First().ContactName == "Maria Anders");
}

[Description("This sample uses SELECT to get Orders as anonymous type")]
public void LinqToEntities14() {
  var query = from o in _em1.Orders
              where o.Customer.Address.City == "London"
              orderby o.OrderDate
              select new { o };

  var r = query.ToList();
  Assert.IsTrue(r.Count() == 46);
  Assert.IsTrue(r.First().o.OrderDate == new DateTime(1996, 8, 26));
}

[Description("This sample uses SELECT to get all Orders and associated Customers as anonymous type")]
public void LinqToEntities15() {
  _em1.DefaultQueryStrategy = QueryStrategy.DataSourceOnly;
  var query = from o in _em1.Orders
              where o.Customer.Address.City == "London"
              orderby o.Customer.CompanyName descending
              select new { o, o.Customer };

  var r = query.ToList();
  Assert.IsTrue(r.Count() == 46);
  Assert.IsTrue(r.First().Customer.CompanyName == "Seven Seas Imports");
}

[Description("This sample uses SELECTMANY to get all Orders for a Customer as a flat result")]
public void LinqToEntities16() {
  _em1.DefaultQueryStrategy = QueryStrategy.DataSourceOnly;
  var query = from c in _em1.Customers
              where c.CustomerID == "ALFKI"
              from o in c.Orders
              orderby o.OrderDate
              select o;

  var r = query.ToList();
  Assert.IsTrue(r.Count() == 6);
  Assert.IsTrue(r.First().OrderDate == new DateTime(1997, 8, 25));
}

[Description("This sample uses SELECTMANY to get all Orders for a Customer as a flat result as a method query")]
public void LinqToEntities17() {
  _em1.DefaultQueryStrategy = QueryStrategy.DataSourceOnly;
  var query = _em1.Customers.Where(cust => cust.CustomerID == "ALFKI")
      .SelectMany(cust => cust.Orders
          .OrderBy(o => o.OrderDate));

  var r = query.ToList();
  Assert.IsTrue(r.Count() == 6);
  Assert.IsTrue(r.First().OrderDate == new DateTime(1997, 8, 25));
}

[Description("This sample uses SELECTMANY to get all Orders for Customers in Denmark as a flat result")]
public void LinqToEntities18() {
  _em1.DefaultQueryStrategy = QueryStrategy.DataSourceOnly;
  var query = from c in _em1.Customers
              where c.Address.Country == "Denmark"
              from o in c.Orders
              orderby o.OrderDate
              select o;

  var r = query.ToList();
  Assert.IsTrue(r.Count() == 18);
  Assert.IsTrue(r.First().OrderDate == new DateTime(1996, 10, 29));
}

[Description("This sample uses SELECTMANY to get all Orders for Customers in Denmark as a flat result as a method query")]
public void LinqToEntities19() {
  _em1.DefaultQueryStrategy = QueryStrategy.DataSourceOnly;
  var query = _em1.Customers.Where(cust => cust.Address.Country == "Denmark")
      .SelectMany(cust => cust.Orders);

  var r = query.ToList();
  Assert.IsTrue(r.Count() == 18);
}


[Description("This sample uses SELECTMANY to get all Orders for Customers in Denmark as a flat result")]
public void LinqToEntities20x() {
  _em1.DefaultQueryStrategy = QueryStrategy.DataSourceOnly;
  var query = from c in _em1.Customers
              where c.Address.Country == "Denmark"
              from o in c.Orders
              where o.Freight > 5
              orderby o.OrderDate
              select o;

  Assert.IsTrue(query.Count() == 17);
  Assert.IsTrue(query.First().OrderDate == new DateTime(1996, 10, 29));
}

[Description("This sample uses SELECTMANY to get all Orders for Customers in Denmark as an anonymous type containing the Orders and Customer flat result")]
public void LinqToEntities21x() {
  _em1.DefaultQueryStrategy = QueryStrategy.Normal.With(QueryInversionMode.Manual);
  var query = from c in _em1.Customers
              where c.Address.Country == "Denmark"
              orderby c.CompanyName
              from o in c.Orders
              where o.Freight > 5
              orderby o.OrderDate
              select new { c, o};

  Assert.IsTrue(query.Count() == 17);
  var x = query.First();
  Assert.IsTrue(query.First().o.OrderDate == new DateTime(1996, 10, 29));
}

[Description("This sample uses SELECTMANY to get all Orders for Customers in Denmark as a flat result using LINQ opeartors")]
public void LinqToEntities22() {
  _em1.DefaultQueryStrategy = QueryStrategy.DataSourceOnly;
  var query = _em1
      .Customers
      .Where(cust => cust.Address.Country == "Denmark")
      .SelectMany(cust => cust.Orders
          .Where(o => o.Freight > 5)
          .OrderBy(o => o.OrderDate));
  var r = query.ToList();
  Assert.IsTrue(r.Count() == 17);
  Assert.IsTrue(r.First().OrderDate == new DateTime(1996, 10, 29));
}