NHibernate 查看生成的sql语句的方法

原创

mb60b79a6396b63 2022-02-22 10:45:43 博主文章分类：Web开发 ©著作权

文章标签 sql hibernate 分页 文章分类 代码人生

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最近想用NHibernate写个快速开发框架。

在做到分页的时候，想利用Nhibernate的分页查询方法，但是又不知道他的分页原理。

主要是数据库分页，还是假分页，这个对性能影响比较大。需要确认下。

但是配置了show_sql=true以后也看不到生成的sql脚本。

貌似必须要配置log4net才行。

后来找到一篇文章。http://zhouweigang01.blog.163.com/blog/static/9340907201223093637530/

介绍了一个借口，很不错，很靠谱。

于是通过此方法进行了一下跟踪，发现确实是数据库分页，虽然是用的rownum，但一般来说性能也够用了。

贴出代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NHibernate;
using NHibernate.SqlCommand;

namespace DAO
{
    [Serializable]
    public class EmptyInterceptor : IInterceptor
    {   //前面省略n行代码 

        public virtual SqlString OnPrepareStatement(SqlString sql)
        {

            return sql;

        }


        public void AfterTransactionBegin(ITransaction tx)
        {
            //throw new NotImplementedException();
        }

        public void AfterTransactionCompletion(ITransaction tx)
        {
            //throw new NotImplementedException();
        }

        public void BeforeTransactionCompletion(ITransaction tx)
        {
            //throw new NotImplementedException();
        }

        public int[] FindDirty(object entity, object id, object[] currentState, object[] previousState, string[] propertyNames, NHibernate.Type.IType[] types)
        {
            //throw new NotImplementedException();
            return null;
        }

        public object GetEntity(string entityName, object id)
        {
            //throw new NotImplementedException();
            return null;
        }

        public string GetEntityName(object entity)
        {
            //throw new NotImplementedException();
            return "";
        }

        public object Instantiate(string entityName, EntityMode entityMode, object id)
        {
            //throw new NotImplementedException();
            return null;
        }

        public bool? IsTransient(object entity)
        {
            //throw new NotImplementedException();
            return true;
        }

        public void OnCollectionRecreate(object collection, object key)
        {
            //throw new NotImplementedException();
        }

        public void OnCollectionRemove(object collection, object key)
        {
            //throw new NotImplementedException();
        }

        public void OnCollectionUpdate(object collection, object key)
        {
            //throw new NotImplementedException();
        }

        public void OnDelete(object entity, object id, object[] state, string[] propertyNames, NHibernate.Type.IType[] types)
        {
            //throw new NotImplementedException();
        }

        public bool OnFlushDirty(object entity, object id, object[] currentState, object[] previousState, string[] propertyNames, NHibernate.Type.IType[] types)
        {
            //throw new NotImplementedException();
            return true;
        }

        public bool OnLoad(object entity, object id, object[] state, string[] propertyNames, NHibernate.Type.IType[] types)
        {
            //throw new NotImplementedException();
            return true;
        }

        public bool OnSave(object entity, object id, object[] state, string[] propertyNames, NHibernate.Type.IType[] types)
        {
            //throw new NotImplementedException();
            return true;
        }

        public void PostFlush(System.Collections.ICollection entities)
        {
            //throw new NotImplementedException();
        }

        public void PreFlush(System.Collections.ICollection entities)
        {
            //throw new NotImplementedException();
        }

        public void SetSession(ISession session)
        {
            //throw new NotImplementedException();
        }
    }
    public class MyInterceptor : EmptyInterceptor
    {

        public override NHibernate.SqlCommand.SqlString OnPrepareStatement(NHibernate.SqlCommand.SqlString sql)
        {
            Console.WriteLine(sql.ToString());
            return base.OnPrepareStatement(sql);

        }

    } 

}