Hibernate: HQL in Depth - Points to Remember
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There are some points to be kept in mind when working with HQL. They are as follows:
1. Queries are case insensitive, barring the Java class and properties’ names. Hence SELECT and select are the same, but Order and order are not.
2. If the class or package does not find a place in imports, then the objects have to be called with the package name. For example, if com.someorg.persist.Order is not imported, then the query would be from com.someorg.persist.Order and so on.
3. A query like
from Foo foo where foo.bar.baz.customer.address.city is
not null
would translate into a SQL query with four joins. So such queries should be used when absolutely necessary, as joins cost heavily in terms of memory and processing.
That’s all for this discussion. In the future I would be covering Criteria queries and advanced HQL. Till then.
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