在本章中，我们将介绍人们将使用的另一个常见API是NHibernate LINQ提供程序.它通过ISession上的扩展方法和签名进行访问是 Query< T> .使用LINQ&minus时有两种语法;
查询链接语法
查询理解语法
您可以使用方法链语法访问数据库中的任何记录，如下所示以下程序.
var customer = session.Query<Customer>() .Where(c => c.FirstName == "Laverne")
你可以看到我们有查询，还有WHERE子句，你可以有额外的WHERE子句和类似的select子句.
这是一种标准的方法链语法，你可以在普通的LINQ中使用.
LINQ to Objects或LINQ to SQL，您可能熟悉的任何其他LINQ提供程序.
让我们看一个简单的例子，我们将检索名字为Laverne的客户.现在我们可能有多个客户的名字是Laverne，所以我们只检索第一个.
using System;
using System.Data;
using System.Linq;
using System.Reflection;
using HibernatingRhinos.Profiler.Appender.NHibernate;
using NHibernate.Cfg;
using NHibernate.Criterion;
using NHibernate.Dialect;
using NHibernate.Driver;
using NHibernate.Linq;
namespace NHibernateDemo {
internal class Program {
private static void Main() {
var cfg = ConfigureNHibernate();
var sessionFactory = cfg.BuildSessionFactory();
using(var session = sessionFactory.OpenSession())
using(var tx = session.BeginTransaction()) {
var customer = session.Query<Customer>()
.Where(c => c.FirstName == "Laverne").First();
Console.WriteLine(customer);
tx.Commit();
}
Console.WriteLine("Press <ENTER> to exit...");
Console.ReadLine();
}
private static Configuration ConfigureNHibernate() {
NHibernateProfiler.Initialize();
var cfg = new Configuration();
cfg.DataBaseIntegration(x => {
x.ConnectionStringName = "default";
x.Driver<SqlClientDriver>();
x.Dialect<MsSql2008Dialect>();
x.IsolationLevel = IsolationLevel.RepeatableRead;
x.Timeout = 10;
x.BatchSize = 10;
});
cfg.SessionFactory().GenerateStatistics();
cfg.AddAssembly(Assembly.GetExecutingAssembly());
return cfg;
}
}
}现在编译并执行上面的代码时，您将看到以下输出./p>
Laverne Hegmann (4e97c816-6bce-11e1-b095-6cf049ee52be) Points: 74 HasGoldStatus: True MemberSince: 4/4/2009 12:00:00 AM (Utc) CreditRating: Neutral AverageRating: 0 Orders: Order Id: 4ea14d96-6bce-11e1-b095-6cf049ee52be Order Id: 4ea14d96-6bce-11e1-b096-6cf049ee52be Order Id: 4ea14d96-6bce-11e1-b097-6cf049ee52be Order Id: 4ea14d96-6bce-11e1-b098-6cf049ee52be Press <ENTER> to exit...
还有查询理解语法，看起来更像SQL使用from，where和select关键字.
所以让我们看看同一个例子，但是这次我们使用LINQ comprehensions语法，它看起来更像SQL，如图所示以下程序.
using System;
using System.Data;
using System.Linq;
using System.Reflection;
using HibernatingRhinos.Profiler.Appender.NHibernate;
using NHibernate.Cfg;
using NHibernate.Criterion;
using NHibernate.Dialect;
using NHibernate.Driver;
using NHibernate.Linq;
namespace NHibernateDemo {
internal class Program {
private static void Main() {
var cfg = ConfigureNHibernate();
var sessionFactory = cfg.BuildSessionFactory();
using(var session = sessionFactory.OpenSession())
using(var tx = session.BeginTransaction()) {
var customer = (from c in session.Query<Customer>()
where c.FirstName == "Laverne" select c).First();
Console.WriteLine(customer);
tx.Commit();
}
Console.WriteLine("Press <ENTER> to exit...");
Console.ReadLine();
}
private static Configuration ConfigureNHibernate() {
NHibernateProfiler.Initialize();
var cfg = new Configuration();
cfg.DataBaseIntegration(x => {
x.ConnectionStringName = "default";
x.Driver<SqlClientDriver>();
x.Dialect<MsSql2008Dialect>();
x.IsolationLevel = IsolationLevel.RepeatableRead;
x.Timeout = 10;
x.BatchSize = 10;
});
cfg.SessionFactory().GenerateStatistics();
cfg.AddAssembly(Assembly.GetExecutingAssembly());
return cfg;
}
}
}现在让我们再次运行此应用程序，您将看到以下输出.
Laverne Hegmann (4e97c816-6bce-11e1-b095-6cf049ee52be) Points: 74 HasGoldStatus: True MemberSince: 4/4/2009 12:00:00 AM (Utc) CreditRating: Neutral AverageRating: 0 Orders: Order Id: 4ea14d96-6bce-11e1-b095-6cf049ee52be Order Id: 4ea14d96-6bce-11e1-b096-6cf049ee52be Order Id: 4ea14d96-6bce-11e1-b097-6cf049ee52be Order Id: 4ea14d96-6bce-11e1-b098-6cf049ee52be Press <ENTER> to exit...
让我们看看另一个例子，我们将检索所有那些FirstName以字母H开头的客户.
using System;
using System.Data;
using System.Linq;
using System.Reflection;
using HibernatingRhinos.Profiler.Appender.NHibernate;
using NHibernate.Cfg;
using NHibernate.Criterion;
using NHibernate.Dialect;
using NHibernate.Driver;
using NHibernate.Linq;
namespace NHibernateDemo {
internal class Program {
private static void Main() {
var cfg = ConfigureNHibernate();
var sessionFactory = cfg.BuildSessionFactory();
using(var session = sessionFactory.OpenSession())
using(var tx = session.BeginTransaction()) {
var customers = session.Query<Customer>() .Where(c =<
c.FirstName.StartsWith("H"));
foreach (var customer in customers.ToList()) {
Console.WriteLine(customer);
}
tx.Commit();
}
Console.WriteLine("Press <ENTER> to exit...");
Console.ReadLine();
}
private static Configuration ConfigureNHibernate() {
NHibernateProfiler.Initialize();
var cfg = new Configuration();
cfg.DataBaseIntegration(x => {
x.ConnectionStringName = "default";
x.Driver<SqlClientDriver>();
x.Dialect<MsSql2008Dialect>();
x.IsolationLevel = IsolationLevel.RepeatableRead;
x.Timeout = 10;
x.BatchSize = 10;
});
cfg.SessionFactory().GenerateStatistics();
cfg.AddAssembly(Assembly.GetExecutingAssembly());
return cfg;
}
}
}同样，查询理解语法类似于以下程序.
using System;
using System.Data;
using System.Linq;
using System.Reflection;
using HibernatingRhinos.Profiler.Appender.NHibernate;
using NHibernate.Cfg;
using NHibernate.Criterion;
using NHibernate.Dialect;
using NHibernate.Driver;
using NHibernate.Linq;
namespace NHibernateDemo {
internal class Program {
private static void Main() {
var cfg = ConfigureNHibernate();
var sessionFactory = cfg.BuildSessionFactory();
using(var session = sessionFactory.OpenSession())
using(var tx = session.BeginTransaction()) {
var customers = from c in session.Query<Customer>()
where c.FirstName.StartsWith("H") select c;
foreach (var customer in customers.ToList()) {
Console.WriteLine(customer);
}
tx.Commit();
}
Console.WriteLine("Press <ENTER> to exit...");
Console.ReadLine();
}
private static Configuration ConfigureNHibernate() {
NHibernateProfiler.Initialize();
var cfg = new Configuration();
cfg.DataBaseIntegration(x => {
x.ConnectionStringName = "default";
x.Driver<SqlClientDriver>();
x.Dialect<MsSql2008Dialect>();
x.IsolationLevel = IsolationLevel.RepeatableRead;
x.Timeout = 10;
x.BatchSize = 10;
});
cfg.SessionFactory().GenerateStatistics();
cfg.AddAssembly(Assembly.GetExecutingAssembly());
return cfg;
}
}
}让我们再次运行此应用程序，您将看到所有客户，其名字开头字母H.
Herman Crooks (4ead3480-6bce-11e1-b15c-6cf049ee52be) Points: 74 HasGoldStatus: True MemberSince: 12/3/2010 12:00:00 AM (Utc) CreditRating: Neutral AverageRating: 0 Orders: Order Id: 4ead3480-6bce-11e1-b15d-6cf049ee52be Order Id: 4ead3480-6bce-11e1-b15e-6cf049ee52be Order Id: 4ead3480-6bce-11e1-b15f-6cf049ee52be Order Id: 4ead3480-6bce-11e1-b160-6cf049ee52be Order Id: 4ead3480-6bce-11e1-b161-6cf049ee52be Order Id: 4ead3480-6bce-11e1-b162-6cf049ee52be Order Id: 4ead3480-6bce-11e1-b163-6cf049ee52be Hudson Bins (4ec03f80-6bce-11e1-b2b7-6cf049ee52be) Points: 56 HasGoldStatus: False MemberSince: 10/20/2008 12:00:00 AM (Utc) CreditRating: Terrible AverageRating: 0 Orders: Order Id: 4ec03f80-6bce-11e1-b2b8-6cf049ee52be Order Id: 4ec03f80-6bce-11e1-b2b9-6cf049ee52be Order Id: 4ec03f80-6bce-11e1-b2ba-6cf049ee52be Order Id: 4ec03f80-6bce-11e1-b2bb-6cf049ee52be Order Id: 4ec03f80-6bce-11e1-b2bc-6cf049ee52be Order Id: 4ec03f80-6bce-11e1-b2bd-6cf049ee52be Order Id: 4ec03f80-6bce-11e1-b2be-6cf049ee52be Order Id: 4ec03f80-6bce-11e1-b2bf-6cf049ee52be Hettie Feest (4ec50240-6bce-11e1-b300-6cf049ee52be) Points: 82 HasGoldStatus: False MemberSince: 4/10/2009 12:00:00 AM (Utc) CreditRating: Neutral AverageRating: 0 Orders: Order Id: 4ec50240-6bce-11e1-b301-6cf049ee52be Order Id: 4ec50240-6bce-11e1-b302-6cf049ee52be Order Id: 4ec50240-6bce-11e1-b303-6cf049ee52be Press <ENTER> to exit...
