如何编写 Nhibernate 查询 [关闭]

Question

我有两个在数据库中映射的类。这些表通过“DeptId”字段相互具有主键和外键关系。

Employee.cs

 public class Employee: Entity
    {
        public virtual Int32 Id { get; set; }
        public virtual string Name { get; set; }
        public virtual string Gender { get; set; }
        public virtual Int32 Age { get; set; }
        public virtual string Designation { get; set; }
        public virtual bool Enabled { get; set; }
        public virtual int CreatedById { get; set; }
        public virtual DateTime CreatedDate { get; set; }
        public virtual int? LastModifiedById { get; set; }
        public virtual DateTime? LastModifiedDate { get; set; }
        public virtual bool IsDeleted { get; set; }
        public virtual Department Department { get; set; }
    }

Department.cs

public class Department
    {
        public virtual int DeptId { get; set; }
        public virtual string DeptName { get; set; }
        public virtual bool Enabled { get; set; }
    }

由于我是 NHibernate 的新手，我无法使用 QueryOver 编写更复杂的 Linq 查询。我已经编写了以下查询，但是如何编写更高级的查询。请为此提供示例查询和参考。

var query = Session.QueryOver<Employee>().List(); 

Answer 1

NHibernate 查询的文档非常好和完整。您可以在这里找到基本知识：

• 章节15. Criteria Queries

QueryOver API 是Criteria 的完全类型化版本，记录在此：

• 章节16. QueryOver Queries

开始观察 API 文档。很快你就会发现这是非常合乎逻辑的（.Where() 构建 WHERE，.Select() 调整 SELECT....）。后来，如果有什么问题，SO 里面全是 HOW TO

从 16.1 调整为 Employee 的示例：

var list = session
        .QueryOver<Employee>()
        .WhereRestrictionOn(c => c.Age).IsBetween(18).And(60)
        .Select(c => c.Name)
        .OrderBy(c => c.Name).Asc
        .List<string>();

到 Department 的 JOIN（从 16.4 调整的示例）

var query = session
        .QueryOver<Employee>()
        .JoinQueryOver(e => e.Department)
            .Where(k => k.DeptName == "Director");

Answer 2

简单的 LINQ 查询被视为 NHibernate 查询，但您必须将它们连接到存储库。

将实体与 Repository 和 IRepository 连接以降低其复杂性。

而且会更有条理。

使用此链接了解实体和存储库之间的联系。 http://www.asp.net/mvc/tutorials/getting-started-with-ef-5-using-mvc-4/implementing-the-repository-and-unit-of-work-patterns-in-an-asp-net-mvc-application

如果我带你走上正轨，请告诉我。

Answer 3

这是完整的示例

using DB.Extensions;
using DB.Modellers;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using FluentNHibernate.Conventions;
using FluentNHibernate.Conventions.Helpers;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Cfg.MappingSchema;
using NHibernate.Mapping.ByCode;
using NHibernate.Tool.hbm2ddl;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;

namespace DB
{
    public class DatabaseAdapter
    {
        public List<IConvention> DatabaseConventions { get; set; }
        ISessionFactory sessionFactory;
        public string SqlFilePath { get; }
        public DatabaseAdapter(string sqlFilePath)
        {
            this.SqlFilePath = sqlFilePath;
            if (sessionFactory == null)
                sessionFactory = InitializeSessionFactory();
        }
       
        public ISession GetSession()
        {
            // For now, this will create a new session - However, eventually we could re-use sessions within threads, HTTP request context, etc
            return sessionFactory.OpenSession();
        }

        public IStatelessSession GetStatelessSession()
        {
            return sessionFactory.OpenStatelessSession();
        }
        ISessionFactory InitializeSessionFactory()
        {
             //var conventions = new IConvention[]
             //{
             //    Table.Is(x => x.EntityType.Name.ToLowerInvariant()), // All table names are lower case
             //    ForeignKey.EndsWith("Id"), // Foreign key references end with Id
             //    DefaultLazy.Always() // Enable Lazy-Loading by default
             //}.Concat(DatabaseConventions.NeverNull()).ToArray();

             var config = Fluently.Configure()
               .Database(GetMonoSQLConfiguration())
               .Mappings(m =>
               {
                   m.FluentMappings.Conventions.Setup(c => c.Add(AutoImport.Never()));
                   m.FluentMappings.Conventions.AddAssembly(Assembly.GetExecutingAssembly());
                   m.HbmMappings.AddFromAssembly(Assembly.GetExecutingAssembly());

                   var assembly = Assembly.Load("DB");
                   m.FluentMappings.Conventions.AddAssembly(assembly);
                   m.FluentMappings.AddFromAssembly(assembly);
                   m.HbmMappings.AddFromAssembly(assembly);
               });
            var nhConfig = config.BuildConfiguration();
            var session = config.BuildSessionFactory();
            return session;
        }
        
        private IPersistenceConfigurer GetMonoSQLConfiguration()
        {
            var sql = SQLiteConfiguration.Standard.UsingFile(this.SqlFilePath)
             .ShowSql();
            return sql;
        }
        public void Dispose()
        {
            if (sessionFactory != null)
                sessionFactory.Dispose();
        }

        public void SaveUpdate()
        {
            using (var session = GetSession())
            {
                using (var transaction = session.BeginTransaction())
                {
                    var existingItem = session.QueryOver<books>()
                       .Where(p => p.number == 1)
                       .Where(p => p.human == "U")
                       .SingleOrDefault();

                    if (existingItem != null) // Update existing
                    {
                        existingItem.number = 1;
                        session.Update(existingItem);
                    }
                    else // Create 
                    {
                        session.Save(new books());
                    }
                    transaction.Commit();
                }
            }
        }
        public IEnumerable<books> GetBooks()
        {
            using (var session = GetStatelessSession())
            {
                var books = session.QueryOver<books>().List();
                return books;
            }
        }
        public IEnumerable<chapters> GetChapters(books books)
        {
            using (var session = GetStatelessSession())
            {
                var items = session.QueryOver<chapters>().Where(p=>p.reference_human == books.human).List();
                return items;
            }
        }
        public IEnumerable<verses> GetVerses()
        {
            using (var session = GetStatelessSession())
            {
                var items = session.QueryOver<verses>().List();
                return items;
            }
        }
    }
}