Spring MVC, Select Special Columns in Native SELECT Query - spring

this is my native SELECT Query in Repository
#Modifying
#Query(value = "SELECT * FROM tasks WHERE title LIKE '%Java%' ORDER BY id DESC ", nativeQuery = true)
List<Task> listAllTasks();
this works ok, but when I use custom column name instead of *, like this
#Modifying
#Query(value = "SELECT title FROM tasks WHERE title LIKE '%Java%' ORDER BY id DESC ", nativeQuery = true)
List<Task> listAllTasks();
I have this error :
org.postgresql.util.PSQLException: The column name id was not found in this ResultSet.
any Help?

The resultset doesn't have the "id" in it, you have to provide it.
You should change the way you are declaring your SQL:
SELECT t.title, t.id FROM tasks t WHERE t.title LIKE '%Java%' ORDER BY t.id DESC
Check out this sort example:Native Queries

Select * from Entity -> returns a List of Entity
Example:
#Query(select * from tasks)
List<Task> findAllTasks();
Select column from Entity -> returns a List of Types of the entity.
Example:
#Query(select t.title from tasks t)
List<String> findTitle_AllTasks();
title is of the type String
Select multiple columns from Entity -> returns an Object[] holding the data
Example:
#Query(select t.id, t.title from tasks t)
List<Object[]> findIdTitle_AllTasks();
So, you are retrieving String type data - title and asking to return a List of Task type. This is causing the problem. You can actually check the hibernate docs under HQL and JPQL to understand this.
Plus, you are doing a SELECT (DQL operation). #Modifying is rudimentary here as it is used for DML operations using Data JPA - UPDATE/DELETE.

Related

List of multiple column condition in query (kind of batch)

when trying to search with single record then this query works
#Query(value = "select * from table t where t.column1 = :column1 and t.column2 = :column2 and t.column3 = :column3")
Flux<Invoice> findByMultipleColumn(#Param("column1”) String column1, #Param("column2”) String column2, #Param("column3”) String column3);
But when I have list of criterias instead of a single row condition then I have to loop over the list of criterias & call the above query multiple times which is not feasible solution.
Sudo code
for (Criteria criteria : criteriaList) {
repository.findByMultipleColumn(criteria.getColumn1(), criteria.getColumn2(), criteria.getColumn3());
}
What I am trying to find a way to solve the above query for multiple LIST of all the 3 column criteria pair, something like below (this is not working solution)
#Query(value = "select * from table t where t.column1 = :column1 and t.column2 = :column2 and t.column3 = :column3")
Flux<Invoice> findByMultipleColumn(#Param List<Table> table);
Is there any way somehow we can try to achieve the above case?
Would be doable if column1, 2 and 3 were Embedded, then you could do
#Query(select * from Entity where embeddedProperty in (:values))
Flux<Entity> findByEmbeddedPropertyIn(Collection<EmbeddedClas> values);
Which would generate the following native SQL clause
Where (column1, column2, column3) in ((x, y, z), ...)
If you don't want to pack these fields i to an embeddable class, you can also try to do a workaround
#Query(select * from Entity where Concat(column1, ';', column2, ';', column3) in (:parametersConcatrenatedInJava)
Flux<Entity> findBy3Columns(Collection<String> parametersConcatrenatedInJava);
It's ofcourse not bulletproof, all three columns could have ";" as their values, this might be problematic if their type is not string, etc.
Edit.:
Third option is to use specification api. Using the criteria builder you can concatenate multiple and / or queries. And pass that specification as an argument to the repository that extends JpaSpecificationExecutor (if you're fetching whole entities) or an entity manager if you're using projections. Read more about specifications

cant using "LIKE" in native query spring boot

I try to get orders of user by query :
#Query(value = "SELECT * FROM ORDERS WHERE USER_ID = ?1 AND CAST(CREATE_AT AS NVARCHAR(100)) LIKE ?2 OR CAST(GRAND_TOTAL AS NVARCHAR(100)) LIKE ?2 OR CAST(STATUS AS NVARCHAR(100)) LIKE ?2" , nativeQuery = true)
Page<Order> getOrdersByUserSearch(int userID, String searchS, Pageable pageable);
But it always return empty list. i run this code in SQL server and it work (?1 =2. ?2 = '2021-06-26').
If I try to change "NOT LIKE" instead of "LIKE" It run.
I dont want using query ( not native), Named query or specification method because it get more error.
Any advice?.
SQL like query requires % along with the value for a match. In case of ordered parameters in queries we can use:
#Query("SELECT m FROM Movie m WHERE m.rating LIKE ?1%")
List<Movie> searchByRatingStartsWith(String rating);
Click here for more info.
In your case the query string should be like this:
SELECT * FROM ORDERS WHERE USER_ID = ?1 AND CAST(CREATE_AT AS NVARCHAR(100)) LIKE %?2% OR CAST(GRAND_TOTAL AS NVARCHAR(100)) LIKE %?2% OR CAST(STATUS AS NVARCHAR(100)) LIKE %?2%

HQL Select New doesn't return row when a foreign key is null

I have the following named query
#NamedQuery(name = "UserFlight.getUserFlightDetails",
query = "SELECT new com.foobar.UserFlightDetails(uf.flight.divertedAirport, uf.flight.number) " +
"FROM UserFlight uf WHERE uf.user.id=?1 AND uf.flight.id=?2")
The UserFlightDetails constructor is as follows
public UserFlightDetails(Airport airport, String flightNumber) {
this.setDivertedAirport(airport);
this.setFlightNumber(flightNumber);
}
divertedAirport is a foreign key in the flight table, path=(uf.flight.divertedAirport)
My problem is when divertedAirport is null (it's a nullable foreign key), my HQL query returns null as the result (The code doesn't even trigger the constructor above), so I don't get the flightNumber which is never null.
If the divertedAirport isn't null, I get both the airport and the flight number fine (and the above constructor gets executed just fine).
What could be causing this and how could I resolve it? I tried some null functions like nullif and coalesce but nothing helped.
I'm using spring boot 1.2.7, hibernate-core 4.3.11.Final
Probably, the problem is the uf.flight.divertedAirport. This expression do a JOIN between flight and divertedAirport but, as you say, divertedAirport is a fk and can be null.
So, you need to use the LEFT JOIN.
I would rewrite your query like this:
#NamedQuery(name = "UserFlight.getUserFlightDetails",
query =
"SELECT new com.foobar.UserFlightDetails(divertedAirport, flight.number)
FROM UserFlight uf
JOIN uf.flight flight
LEFT JOIN flight.divertedAirport divertedAirport
JOIN uf.user user
WHERE user.id = ?1 AND flight.id = ?2 ")
I remove the references like uf.user.id for a explicit JOIN (JOIN uf.user user plus user.id), because is more legible and this kind of problem that generated your question is more easy to find using this way to write JPQL queries.

entity framework lazy loading null properties in child

Using entity framwork with lazy loading - Have the following question on loading related entities when the entities
are null.
Say I have two tables employee and employeedetails. Assume in the above case not all employee entries have an entry in the employeedetails table.
If I want to look up a list of Employees
(from e in objectcontext.employees
select new EmployeeEntity
{
EmpID= e.EmployeeID,
FirstName = e.FirstName,
Address = e.employeedetails.Address
}).ToList();
EmployeeEntity is the data class into which we stuff the results.
The above code breaks if even one employee in the returned list
does not have a entry in table employeedetails. This is obvious since e.employeedetails will be null for those customers who do not have a details entry
What is the best way to rewrite the above query?
Would something like this be acceptable ?
(from e in objectcontext.employees
select new EmployeeEntity
{
EmpID= e.EmployeeID,
FirstName = e.FirstName,
Address = e.employeedetails == null ? "" : e.employeedetails.Address,
}).ToList();
I am not clear on the efficiency of this above query - Would this statment do the null check at DB level?
Should I instead do an explicit include like
objectcontext.include("employeedetails")...
And then loop through the results to check for null?
Yes, this statement would indeed perform a null check in the SQL query that is generated. Most likely, it will simply be a NVL or COALESCE.
That's the way you should be doing it.

How to write Order by expression in JPQL

PostgreSQL and MySQL offers to write expression into ORDER BY clause in SQL query. It allows to sort items by some column but the special values are on the top. The SQL looks like this one. ( works in Postgres )
select * from article order by id = 4, id desc;
Now I want to write it in the JPQL but it doesn't work. My attempt is:
#NamedQuery(name = "Article.special", query = "SELECT a FROM Article a ORDER BY ( a.id = :id ) DESC, a.id DESC")
This is JPA 1.0 with Hibernate driver. Application server throws this exception on deploy.
ERROR [SessionFactoryImpl] Error in named query: Article.special
org.hibernate.hql.ast.QuerySyntaxException: unexpected AST node: = near line 1, column 73 [SELECT a FROM cz.cvut.fel.sk.model.department.Article a ORDER BY ( a.id = :id ) DESC, a.id DESC]
at org.hibernate.hql.ast.QuerySyntaxException.convert(QuerySyntaxException.java:54)
Thanks a lot.
For a named query, (ORDER BY ( a.id = :id ) or ORDER BY (:id )) won't work as DSC/ASC can't be parametrized at run-time.
1) Dynamic way if ordering element varies at runtime.
String query = "SELECT a FROM Article a ORDER BY "+orderElement+" DESC, a.id DESC";
entityManager.createQuery(query).getResultList();
2) Static way in entity bean if ordering element is fixed.
Field level:
#OrderBy("id ASC")
List<Article> articles;
Method level:
#OrderBy("id DESC")
public List<Article> getArticles() {...};

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