与成果管理制S+ORM相比,目标数据库的弱点是什么?

最大的弱点是缺乏标准化<>>:没有标准文本、没有标准查询语言(口服体液酸液的尝试是重大失败),因此缺乏可移动性和可操作的工具(用于备份、存档、移徙等)。 在数据方面,你并不希望。

这就解释了海事组织为何从收养角度看,房舍管理处是失败的,以及为什么房舍管理司将留守,而不管NSQL运动如何(我感觉到,房舍管理处供应商认为NSQL运动是在其产品重新销售后回来的机会)。

我的经验:

• RDBMS:
  • Frankly, I don t like working with SQL, a 15-year old language, but the reality is that you re forced to if you want anything usable, such as bulk inserts (the LINQ-to-Entity ORM framework does not support bulk inserts, so it takes 30 seconds for a 20,000 record insert, compared to 500ms for a bulk insert in SQL). You end up having to use ADO.NET for database insertions.
  • There are some advantages of an RDBMS over an object database, namely, the data is independent of the calling application (however, this is a weakness also, as the mapping layer makes everything slower, more complex, and more brittle).
  • Bottom line: Spent 6 weeks with the LINQ-to-Entity ORM framework and Microsoft SQL Server 2008 R2. Reasonably steep learning curve.
• Object databases: Tried an object database, namely, the free, open source db4o.
  • Discovered that I could persist my objects with one line of code.
  • No schema changes to deal with, it just worked.
  • Instant support for POCO (Plain Old Class Objects). Create your class in code, then persist it. Its possible to do the same with the Entity framework, however, its a lot of work with manual mapping, and it breaks very easy.
  • Turn on transparent persistence, and it has automatic lazy loading in the background - no more checking for objects that are not loaded because of lazy loading in the Entity framework.
  • The performance of object databases is also impressive: if you have 10 million rows in an object database, and indexing turned on, its 16ms for a three-column select. That s decent.
  • Bottom line: After 1 week I had the same solution as using a RDBMS for persistence, however, it was much cleaner, much less code, and more maintainable - and if I really wanted, I could use use a service to synchronize the db4o database with MSSQL.

关于企业世界中真正的大型系统,包括表格中的2.5亿英亩,例如sharding;以及

我怀疑供应商没有接受目标数据库的原因之一,因为数据库市场每年价值30亿美元,现在没有理由杀害现金。