Python Javascript Linux Cheat sheet Contact. I guess you just needed a new clean run to pick up the query changes ;- The below code absolutely works and it is great if you keep all your queries in orm. Notes: The issue may be a specific MySql quirk. I only tested with Oracle. Tags: Java Hibernate Null. Why isn't there a openjdkjdk package on debian anymore? FAQ Search. Page 1 of 1. Previous topic Next topic. Post subject: HQL query for "x is null or x.
In contrast, when I use the query "from Data as data where data. Sadly, I cannot use some patch like creating an empty "info" class for every "data" to avoid the problem.
Is there any way to write a single query in which the where clause is in the form "x is null or x. Regards, Oz. Java public static final constants eg. Similarly, is null and is not null can be used to test for null values.
Booleans can be easily used in expressions by declaring HQL query substitutions in Hibernate configuration:. You can test the size of a collection with the special property size or the special size function. For indexed collections, you can refer to the minimum and maximum indices using minindex and maxindex functions. Similarly, you can refer to the minimum and maximum elements of a collection of basic type using the minelement and maxelement functions.
The SQL functions any, some, all, exists, in are supported when passed the element or index set of a collection elements and indices functions or the result of a subquery see below :.
Note that these constructs - size , elements , indices , minindex , maxindex , minelement , maxelement - can only be used in the where clause in Hibernate3. Elements of indexed collections arrays, lists, and maps can be referred to by index in a where clause only:.
The expression inside [] can even be an arithmetic expression:. HQL also provides the built-in index function for elements of a one-to-many association or collection of values. Consider how much longer and less readable the following query would be in SQL:. The list returned by a query can be ordered by any property of a returned class or components:. The optional asc or desc indicate ascending or descending order respectively.
A query that returns aggregate values can be grouped by any property of a returned class or components:. SQL functions and aggregate functions are allowed in the having and order by clauses if they are supported by the underlying database i. Neither the group by clause nor the order by clause can contain arithmetic expressions.
Hibernate also does not currently expand a grouped entity, so you cannot write group by cat if all properties of cat are non-aggregated. You have to list all non-aggregated properties explicitly. For databases that support subselects, Hibernate supports subqueries within queries. A subquery must be surrounded by parentheses often by an SQL aggregate function call. Even correlated subqueries subqueries that refer to an alias in the outer query are allowed.
Note that subqueries can also utilize row value constructor syntax. Hibernate queries can be quite powerful and complex. In fact, the power of the query language is one of Hibernate's main strengths. The following example queries are similar to queries that have been used on recent projects. Please note that most queries you will write will be much simpler than the following examples. The following query returns the order id, number of items, the given minimum total value and the total value of the order for all unpaid orders for a particular customer.
The results are ordered by total value. In determining the prices, it uses the current catalog. What a monster! Actually, in real life, I'm not very keen on subqueries, so my query was really more like this:. If the statusChanges collection was mapped as a list, instead of a set, the query would have been much simpler to write. The next query uses the MS SQL Server isNull function to return all the accounts and unpaid payments for the organization to which the current user belongs.
HQL now supports update , delete and insert If your database supports subselects, you can place a condition upon selection size in the where clause of your query:. As this solution cannot return a User with zero messages because of the inner join, the following form is also useful:.
Collections are pageable by using the Query interface with a filter:. Components can be used similarly to the simple value types that are used in HQL queries. They can appear in the select clause as follows:. Components can also be used in the where clause:.
Another common use of components is in row value constructors. Here, we are generally referring to multi-valued comparisons, typically associated with components.
Consider an entity Person which defines a name component:. That is valid syntax although it is a little verbose. You can make this more concise by using row value constructor syntax:. It can also be useful to specify this in the select clause:. Using row value constructor syntax can also be beneficial when using subqueries that need to compare against multiple values:.
One thing to consider when deciding if you want to use this syntax, is that the query will be dependent upon the ordering of the component sub-properties in the metadata. Chapter Case Sensitivity The from clause
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