Linq Expression to NHibernate数据上下文中的SQL文本

Question

Assuming that I have setup NHibernate data context with all relations, tables, connection etc.

How I would convert an instantiated .NET Expression (actually it's not a full SELECT but just a WHERE expression) to an SQL string?

I've seen many references. Like using ExpressionVisitor or building IQueryable Provider, but I believe NHibernate 3 has all these implementations and I just have to combine some classes to achieve the goal. Ant ideas?

Answer 1

Well, right after posting this question an approach was found here: How can I have NHibernate only generate the SQL without executing it? .

Actually it's possible to get a text only for the full SELECT query, otherwise the exception is raised:

Cannot parse expression '(rec.Id == 6)' as it has an unsupported type. Only query sources (that is, expressions that implement IEnumerable) and query operators can be parsed.

Answer 2

查看有关如何通过编写自定义批处理程序来拦截sql查询的其他答案： NHibernate和拦截器-测量/监视SQL往返时间它也适用于Sql Server，一旦拦截了查询，您就可以自由地阻止其执行返回空结果。