NHibernate 有好几种数据库查询方式

NHibernate 有好几种数据库查询方式

1、原生SQL

var employeeQuery = Database.Session

	.CreateSQLQuery("select * from Employee where FirstName = 'John'")

	.AddEntity(typeof(Employee));

var employees = employeeQuery.List<Employee>();

2、Hibernate Query Language(HQL)HN自己的一条语言，简称HQL

var employeeQuery = Database.Session

	.CreateQuery("select e  from Employee as e");

var employees = Database.Session

	.CreateQuery("select e from Employee as e ")

	.List<Employee>();

//select e from Employee as e where e.Firstname = 'John'

var firstName = "John";

var employees = Database.Session

	.CreateQuery("select e from Employee as e where e.Firstname = '"

	+ firstName

	+ "'")

	.List<Employee>();

var employeeQuery = Database.Session

	.CreateQuery("select e from Employee as e where e.Firstname = :firstName");

employeeQuery.SetParameter("firstName", "John");

var employees = employeeQuery.List<Employee>();

3、Criteria API 标准API

using (var transaction = database.Session.BeginTransaction())

{

  var employeeQuery = database.Session.CreateCriteria<Employee>();

  employeeQuery.Add(Restrictions.Eq("Firstname", "john"));

  var employees = employeeQuery.List<Employee>();

  transaction.Commit();

}

using (var transaction = database.Session.BeginTransaction())

{

  var employees = database.Session.CreateCriteria<Employee>()

  .Add(Restrictions.Eq("Firstname", "john"))

  .List<Employee>();

  transaction.Commit();

}

using (var transaction = database.Session.BeginTransaction())

{

 	var employees = database.Session.CreateCriteria<Employee>()

	.Add(Restrictions.Between("DateOfJoining", DateTime.Now.AddYears(-1), DateTime.Now))

  	.List<Employee>();

  	transaction.Commit();

}

4、The QueryOver API

var employees = Database.Session.QueryOver<Employee>()

.Where(x => x.Firstname == "John")

.List<Employee>();

var employees = Database.Session

.QueryOver<Employee>()

.Where(x => x.DateOfJoining > DateTime.Now.AddYears(-1) &&

x.DateOfJoining < DateTime.Now)

.List<Employee>();

5、LINQ

var employees = from e in Database.Session.Query<Employee>()

        where e.Firstname == "John" select e;

var employees = Database.Session.Query<Employee>()

.Where(e => e.Firstname == "John");

var employees = from e in Database.Session.Query<Employee>()

where e.DateOfJoining > DateTime.Now.AddYears(-1) &&

e.DateOfJoining < DateTime.Now

select e;

var employees = Database.Session.Query<Employee>()

.Where(e => e.DateOfJoining > DateTime.Now.AddYears(-1) &&

e.DateOfJoining < DateTime.Now);