[英]NHibernate Hilo Sequence without NHibernate
I have one application which uses NHibernate to save entities to a database, and it uses the HiLo generate of NHibernate to create the id's. 我有一个应用程序使用NHibernate将实体保存到数据库,它使用HiLo生成的NHibernate来创建id。 I have another application which I need to save data to the same table, however in this application, I'm not using NHibernate.
我有另一个应用程序,我需要将数据保存到同一个表,但是在这个应用程序中,我没有使用NHibernate。 Is there a simple way to use HiLo without adding reference to NHibernate and mapping files?
有没有一种简单的方法来使用HiLo而不添加对NHibernate和映射文件的引用?
<id name="EntityId" unsaved-value="0" >
<column name="EntityId" sql-type="int" not-null="true" />
<generator class="hilo">
<param name="table">hibernate_unique_key</param>
<param name="column">next_hi</param>
<param name="max_lo">1000</param>
</generator>
</id>
Update: I created a new method to get the next id which I believe has the same behavior as the NHibernate HiLo sequence. 更新:我创建了一个新方法来获取下一个id,我相信它具有与NHibernate HiLo序列相同的行为。 I'm not putting any locks on the database, so if this were a high frequency table that I was inserting to, it could be an issue, but for very low frequency, there is a very low possibility that there may be a concurrency issue.
我没有对数据库进行任何锁定,因此如果这是我插入的高频表,则可能是一个问题,但是对于非常低的频率,可能存在并发问题的可能性很小。 。
/// <summary>
/// Gets the next entity id.
/// </summary>
/// <returns></returns>
public static int GetNextAvailableEntityId()
{
int max_lo = 1000;
int nextHi = DefaultContext.Database.SqlQuery<int>("select next_hi from hibernate_unique_key").Single();
int nextRangeStart = max_lo * nextHi;
int currentMax = DefaultContext.Database.SqlQuery<int>("SELECT MAX(entityid) FROM Entities").Single();
if (currentMax < nextRangeStart)
{
return currentMax + 1;
}
else
{
DefaultContext.Database.ExecuteSqlCommand("update hibernate_unique_key set next_hi = next_hi + 1");
return nextHi;
}
}
If in doubt, take a look at NH's code to be sure that you implement it correctly. 如果有疑问,请查看NH的代码,以确保您正确实现它。
It is something like this: 它是这样的:
You can create a single instance of an id generator for all transaction of the same process. 您可以为同一进程的所有事务创建一个id生成器的单个实例。 Make sure that your id generator is thread safe.
确保您的id生成器是线程安全的。
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