<\/div>\n

Merhaba,<\/p>\n

Uygulamalarda kullan\u0131lan ORM’ler her ne kadar bizlerin yerine sorgu \u00fcretip, \u00e7al\u0131\u015ft\u0131rsa da bazen sunucu taraf\u0131nda haz\u0131r bir query bar\u0131nd\u0131ran view yahut stored procedure gibi yap\u0131lanmalardan gelen result’lar\u0131n da ORM vas\u0131tas\u0131yla Entity Type misali kullan\u0131lmas\u0131 ihtiya\u00e7 olabilmektedir. \u0130\u015fte bu durumda, Entity Framework Core 2.1 ile Query Types<\/em> olarak hayat\u0131m\u0131za giren ve 3.1 s\u00fcr\u00fcm\u00fcnde Keyless Entity Types<\/em> olarak tekrar isimlendirilen \u00f6zellik ile bu ihtiya\u00e7 desteklenmi\u015f ve rahat\u00e7a \u00e7\u00f6z\u00fclebilir hale getirilmi\u015ftir.<\/p>\n

Keyless Entity Types; normal entity type’lara ek olarak, primary key i\u00e7ermeyen query’lere kar\u015f\u0131 veritaban\u0131 sorgular\u0131 y\u00fcr\u00fctmek i\u00e7in kullan\u0131labilmektedir.<\/em><\/p><\/blockquote>\n

Genellikle group by<\/code>, pivot<\/code> vs. gibi i\u015flemlerle yap\u0131lan istatistiksel \u00e7al\u0131\u015fmalar neticesinde \u00fcretilen veriler primary key bar\u0131nd\u0131rmayan sorgu sonu\u00e7lar\u0131 do\u011furmaktad\u0131rlar. Bizler bu tarz sorgular\u0131 Keyless Entity Types<\/em> \u00f6zelli\u011fi ile sanki bir entity’e kar\u015f\u0131l\u0131k geliyormu\u015f gibi Entity Framework Core yap\u0131lanmas\u0131na dahil edebiliyor ve \u00e7al\u0131\u015fmalar\u0131m\u0131z\u0131 ger\u00e7ekle\u015ftirebiliyoruz.<\/p>\n

\u0130lgili \u00f6zelli\u011fi \u00f6rneklendirebilmek i\u00e7in direkt bir senaryo \u00fczerinden pratikle\u015ftirelim. \u015e\u00f6yle ki; ‘Employees’ ve ‘Sales’ olmak \u00fczere aralar\u0131nda bire \u00e7ok ili\u015fki olan iki adet tablo ve bir adet, sunucuda hangi employee’un ka\u00e7 adet sat\u0131\u015f yapt\u0131\u011f\u0131n\u0131 hesaplayan bir group by i\u015flemi yapan view tasarlayal\u0131m.<\/p>\n

Buyrun ba\u015flayal\u0131m…<\/p>\n

Entityler;<\/p>\n

\r\n    public class Employee\r\n    {\r\n        public int Id { get; set; }\r\n        public string Name { get; set; }\r\n        public string Surname { get; set; }\r\n        public int Position { get; set; }\r\n        public ICollection<Sale> Sales { get; set; }\r\n    }\r\n<\/pre>\n\r\n    public class Sale\r\n    {\r\n        public int Id { get; set; }\r\n        public int EmployeeId { get; set; }\r\n        public string SaleExplanation { get; set; }\r\n        public Employee Employee { get; set; }\r\n    }\r\n<\/pre>\nContext nesnesi;<\/p>\n
\r\n    public class CompanyContext : DbContext\r\n    {\r\n        public DbSet<Employee> Employees { get; set; }\r\n        public DbSet<Sale> Sales { get; set; }\r\n\r\n        protected override void OnModelCreating(ModelBuilder modelBuilder)\r\n        {\r\n            modelBuilder.Entity<Employee>().HasData(\r\n                new Employee { Id = 1, Name = "Hilmi", Surname = "Celayir" },\r\n                new Employee { Id = 2, Name = "H\u00fcseyin", Surname = "S\u00fcmer" },\r\n                new Employee { Id = 3, Name = "\u015euayip", Surname = "Aldatmaz" }\r\n                );\r\n            modelBuilder.Entity<Sale>().HasData(\r\n                new Sale { Id = 1, EmployeeId = 1 },\r\n                new Sale { Id = 2, EmployeeId = 2 },\r\n                new Sale { Id = 3, EmployeeId = 3 },\r\n                new Sale { Id = 4, EmployeeId = 1 },\r\n                new Sale { Id = 5, EmployeeId = 2 },\r\n                new Sale { Id = 6, EmployeeId = 3 },\r\n                new Sale { Id = 7, EmployeeId = 3 },\r\n                new Sale { Id = 8, EmployeeId = 3 },\r\n                new Sale { Id = 9, EmployeeId = 1 }\r\n                );\r\n\r\n            base.OnModelCreating(modelBuilder);\r\n        }\r\n        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)\r\n        {\r\n            optionsBuilder.UseSqlServer("Server=.;Database=CompanyDb;Trusted_Connection=True;");\r\n            base.OnConfiguring(optionsBuilder);\r\n        }\r\n    }\r\n<\/pre>\nBu tasar\u0131mlardan sonra Package Manager Console \u00fczerinden add-migration mig_1<\/code> talimat\u0131n\u0131 verelim ve olu\u015fturulan migration’\u0131n ‘Up’ fonksiyonunun en son sat\u0131r\u0131na a\u015fa\u011f\u0131daki ‘View_EmployeeSales’ isimli view’i olu\u015fturan kodlar\u0131 yerle\u015ftirelim.<\/p>\n
\r\nusing Microsoft.EntityFrameworkCore.Migrations;\r\n\r\nnamespace KeylessEntityTypes.Migrations\r\n{\r\n    public partial class mig_1 : Migration\r\n    {\r\n        protected override void Up(MigrationBuilder migrationBuilder)\r\n        {\r\n            .\r\n            .\r\n            .\r\n            migrationBuilder.Sql(@"CREATE VIEW View_EmployeeSales\r\n                                   AS\r\n                                   SELECT e.Name, COUNT(*) [Total Sales] FROM Employees e\r\n                                   JOIN Sales s\r\n                                   ON e.Id = s.EmployeeId\r\n                                   GROUP BY e.Name\r\n                                ");\r\n        }\r\n    }\r\n}\r\n<\/pre>\nVe son olarak update-database<\/code> talimat\u0131yla tasarlanan yap\u0131y\u0131 migrate edelim.<\/p>\n
\u015eimdi olu\u015fturulan veritaban\u0131nda ‘View_EmployeeSales’ view’ini sorgulayal\u0131m ve nas\u0131l bir sonu\u00e7 geldi\u011fini hep beraber g\u00f6zlemleyelim.
\n<\/a>
\nEvet… G\u00f6r\u00fcld\u00fc\u011f\u00fc \u00fczere bu sonucu Entity Framework Core ORM’sinin ‘Keyless Entity Types’ \u00f6zelli\u011fi sayesinde bir entity ile e\u015fle\u015ftirecek ve daha rahat sorgulayabilece\u011fiz.<\/p>\n
Bunun i\u00e7in devam edelim…<\/p>\n
\u00d6ncelikle sorgu sonucuna uygun modelde bir entity tasarlayal\u0131m. Misal ‘EmployeeSale’ isminde olabilir…<\/p>\n
\r\n    public class EmployeeSale\r\n    {\r\n        public string Name { get; set; }\r\n        public int TotalSales { get; set; }\r\n    }\r\n<\/pre>\nArd\u0131ndan bu entity’i context nesnesine hem DbSet olarak ekleyelim hem de override edilen ‘OnModelCreating’ metodu i\u00e7erisinde entity’e uygun a\u015fa\u011f\u0131daki konfig\u00fcrasyonlar\u0131 ger\u00e7ekle\u015ftirelim.<\/p>\n\r\n    public class CompanyContext : DbContext\r\n    {\r\n        public DbSet<Employee> Employees { get; set; }\r\n        public DbSet<Sale> Sales { get; set; }\r\n        public DbSet<EmployeeSale> EmployeeSales { get; set; }\r\n        protected override void OnModelCreating(ModelBuilder modelBuilder)\r\n        {\r\n            modelBuilder.Entity<EmployeeSale>(es =>\r\n                es.HasNoKey()\r\n                  .ToView("View_EmployeeSales")\r\n                  .Property(p => p.TotalSales).HasColumnName("Total Sales"));\r\n            .\r\n            .\r\n            .\r\n<\/pre>\nYukar\u0131daki kod blo\u011funu incelerseniz e\u011fer, 5.<\/strong><\/em> sat\u0131rda ilgili entity DbSet olarak eklenmekte ve 8.<\/strong><\/em> sat\u0131rda ise eklenen entity’nin konfig\u00fcrasyonlar\u0131 ger\u00e7ekle\u015ftirilmektedir. 9.<\/strong><\/em> sat\u0131rda ‘HasNoKey’ fonksiyonu ile ilgili entity’nin bir primary key’i olmad\u0131\u011f\u0131n\u0131, 10.<\/strong><\/em> sat\u0131rda sunucudaki ‘View_EmployeeSales’ isimli view’e kar\u015f\u0131l\u0131k geldi\u011fini ve 11.<\/strong><\/em> sat\u0131rda ise ‘Total Sales’ olarak gelen kolonun ‘TotalSales’ propertysi ile e\u015fle\u015fmesi gerekti\u011fini ifade etmekteyiz.<\/p>\nSonu\u00e7 olarak yap\u0131lan bu in\u015fa neticesinde ilgili DbSet’i sorgularsak e\u011fer;
\n<\/a>
\n\u015feklinde sonu\u00e7lar\u0131 ba\u015far\u0131yla alabilmekteyiz.<\/p>\n
Ayr\u0131ca burada primary key olmayan veri illa ki bir view’den de\u011fil, LINQ sorgusundan da geliyor olabilir… Evet, yanl\u0131\u015f okumad\u0131n\u0131z \ud83d\ude42 Keyless Entity Types \u00f6zelli\u011fini kullanabilmek i\u00e7in arkada \u00e7al\u0131\u015facak olan query bir view olaca\u011f\u0131 gibi bir LINQ sorgusuda olabilir.<\/p>\n
Bunun i\u00e7in ‘OnModelCreating’ metodunda yap\u0131lan konfig\u00fcrasyonun a\u015fa\u011f\u0131daki gibi de\u011fi\u015ftirilmesi yeterli olacakt\u0131r.<\/p>\n
\r\n            modelBuilder.Entity<EmployeeSale>(es =>\r\n                es.HasNoKey()\r\n                  .ToQuery(() => Sales.GroupBy(s => s.Employee.Name)\r\n                                      .Select(es => new EmployeeSale\r\n                                      {\r\n                                          Name = es.Key,\r\n                                          TotalSales = es.Count()\r\n                                      })));\r\n<\/pre>\nG\u00f6r\u00fcld\u00fc\u011f\u00fc \u00fczere ‘ToQuery’ fonksiyonu sayesinde herhangi bir view’e ba\u011f\u0131ml\u0131l\u0131k olmaks\u0131z\u0131n LINQ ile sorgu olu\u015fturulabilmektedir.<\/p>\n
[Keyless] Attribute’u<\/h5>\nPrimary key’i olmayan entity’ler de ‘OnModelCreating’ \u00fczerinden ‘HasNoKey’ fonksiyonu ile bildirim yap\u0131lmas\u0131na alternatif olarak ‘Keyless’ attribute’u \u00fcretilmi\u015ftir. Bu attribute sayesinde primary key’i olmayan entity direkt i\u015faretlenerek bildiride bulunulabilmektedir.<\/p>\n
\r\n    [Keyless]\r\n    public class EmployeeSale\r\n    {\r\n        public string Name { get; set; }\r\n        public int TotalSales { get; set; }\r\n    }\r\n<\/pre>\n\u0130lgilenenlerin faydalanmas\u0131 dile\u011fiyle…
\nSonraki yaz\u0131lar\u0131mda g\u00f6r\u00fc\u015fmek \u00fczere…
\n\u0130yi \u00e7al\u0131\u015fmalar…<\/p>\n","protected":false},"excerpt":{"rendered":"
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