I am using spring boot, spring data JPA, I am searching for solution to get all column names of a given table. But could not found as per my requirements
Not want a solution with native query.Looking for general solution using spring data abstraction.
I am able to get the column names using normal java but i want to fetch them using spring data JPA.
they are several ways
public interface TableMetadataRepository extends JpaRepository<TableMetadata, TableMetadataKey>
{
TableMetadata findByTableName(String tableName);
}
then you can go for
List<TableMetadata> metadata = tableMetadataRepository.findAll()
TableMetadata metadataofspecifictable = tableMetadataRepository.findByTableName("urtable");
Related
I'm developing a Spring Boot application with Spring Data JPA. I want to return the promedio field when the calificacionSemestral1 field is a specific value and the calificacionSemestral2 field is a specific value.
Entity
DER
Doing this using JPQL is it possible?
I know that I can create a DTO with the same fields or do two queries, but I want to avoid doing it if I can get the result in a single query.
I have spring boot application with JPA and MySQL. The table is already created and data are present. From the spring boot application, we need to create two API - get a particular record using id and get all the records. I created a model class but confused with usage of #Entity. Because I'm not going to insert/delete a record from the database. I want to use only for select the record.
For Select query (findBy), do we need to use #Entity annotation at the top of model class?
Yes, you would need to use #Entity to mark your model class, this tells JPA that your class is used for mapping to and from a database table. If you want to make sure that you don't accidentally overwrite the data, you could implement a check via #EntityListener, as described in this answer.
how would you approach problem of simple app, allowing users to summarise/calculate average of price values of inventory stored? MVC model, Spring, H2. Do I need Hibernate to achieve that? How to access fields of particular items stored?
Is it a requirement to use H2? If no, just 'read' the inventory and calculate on the fly. Build the minimal solution.
If yes, I personally prefer to go with Spring Boot / Spring Data / Hibernate as this is widely used and better to maintain than a self-build solution. You could get the information with a custom query at the repository - something like:
#Query(value = "SELECT AVG(price) FROM product")
public Double getAveragePrice();
With https://bootify.io you can setup your Spring Boot app with the database model, and can add the custom logic on top.
I have a Spring Boot application and I am using Spring Data JPA to query a PostgreSQL database.
I have a column of List type in my database. Now I need a query to search all those rows where my input parameter is present in this list.
eg. I have a column of type List containing any of these values: ["cat","dog","cow"].
I need to find all those rows where "cat" is one among the list.
Can you help me with the format of this query? Thanks in advance.
From what I could understand, you have a DB table, let's say Sample. Now this table has multiple columns with one column whose values can be either of "cat","dog","cow". Let's assume the column name to be 'sampleName'.
So, in your code you must be having an #Entity class for Sample with #Column sampleName, and a corresponding JPA repository - SampleRepository.
Now, the code for requirement should look like as shown below:
public interface SampleRepository extends JpaRepository<Sample, Long> {
Optional<Sample> findBySampleName(String sampleName);
}
In above JPA repository, I have assumed that you have an #Id field of type Long in your entity Sample. Also, I have made use of method-name strategy. Spring boot will automatically translate this method name to a SQL query at run time like - SELECT * FROM sample WHERE sampleName = 'cat'. This value cat will be provided to your repository method as an argument from #Service layer.
Hope this helps!
In addition to this, you can also choose to use the native query approach. Please refer - https://www.baeldung.com/spring-data-jpa-query for more details.
I have a set of Entities generated using Spring ROO. After several commands, basically using web mvc, I have a set of links to get the contents from a database. I need to order the contents according to title, instead of the order in the table. How can I do it? Is there any Spring ROO commando or annotation to order the items.
For more information, I am using Spring Roo 1.2.1, and the finder I got is the following.
public static List<Deporte> Deporte.findAllDeportes() {
return entityManager().createQuery("SELECT o FROM Deporte o", Deporte.class).getResultList();
}
Thanks in advance.
Spring Roo uses JPA for the persistence. Search for JPA tutorials and documentation to find what you're looking for.
JPQL uses the order by clause to order results returned by a query. This order by is very similar to the SQL order by clause:
SELECT o FROM Deporte o order by o.title