Recently I found no obvious behaviour when using ‘select new/constructor expression’ in jpa/hibernate. It uses kind of lazy loading for each entity in each row in result set what is not efficient. Test example First case we issue a query using select new technique: This issues one query to fetch o…
Tag: jpql
JPQL issue updating records
Trying to update a record in a database but getting this error: Code below is responsible for inserting it Im not sure if there is a type issue with propId being a Long or if i have written the SQL paths wrong or both. Answer You’re trying to execute an SQL query as JPQL. There are a couple options to
JPQL query that give me the highest value
I’m trying to do a JPQL query that give me the highest PK of the PKs in my table (https://drive.google.com/file/d/1_kaklkKdCbhT0-byqCtz6HgfluKKp8J-/view?usp=sharing). Here is my query : The error says that the syntax of my query is wrong. Can someone please help me ? Thank you for your help 🙂 Answer Tha…
Does JPQL support the use of a boolean result in another expression?
I am trying to write a query to back a search API. Specifically for a flag searchDrafts – if the flag is true I have to get rows with status DRAFT and else I have to get all rows that have any status other than DRAFT. In regular SQL, the below query works fine: However, a similar thing in JPQL
Showing a specific JSON response for my GET endpoint
I have a many-to-many relationship between Department and Employee I have already done a mapping for the GET endpoint which returns a list of departments that contain Employees, this is the request: http://localhost:8080/api/departments/1/employees, and this is the response I get: This is the code that gets t…
Spring Data JPA sorting by property without hardcoding
I have entity that has several fields: I want to have code which is capable to sort by foo and sort by bar depending on the request. I know that there is tool that could be used like this: But it seems like this approach is not perfect because field names are hardcoded and in the case that some field
How to handle an error when database returns null value for one of the columns in the table
I’m using Java and Spring Boot with JPQL to access the data. I’m getting the below error because hourlyRate is null in the database: Caused by: org.hibernate.QueryException: could not instantiate class [com.example.model.response.school.Employee] from tuple. I still would like to be able to get th…
How use generic entity name in JPQL
I have three tables with same column name and types, what changes is just the table name. Example: | TABLE1 | TABLE2 | TABLE3 | | —— | —— | ——- | | ID | ID | ID | | NAME | NAME | NAME | | FOO | FOO | FOO | | BAR | BAR | BAR |
Passing a query as a query parameter in JPQL Native Query
I’m trying to pass a query as a string parameter in another JPQL native query. So the resulting query would be something like the query below that returns me a value but what I’m getting in return is only the string of :query parameter and not the result of the executed complete query. Answer Crea…
How to check UUID null value in JPQL?
I am using JPA/Hibernate. So I wanna to do nullCheck in JPQL, but when I do that it does not determine dataType. JPQL Query: EXCEPTION: Caused by: org.postgresql.util.PSQLException: ERROR: could not determine data type of parameter $1 at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecu…