I am using Mysql, Springboot with JPA Hibernate.
Now to query using JPA, I have 2-3 options:
Using functionNames as direct query like findById() and soon
Using JPQL
Using Native Query in my SpringBoot JPA Repository (using nativeQuery = true)
Using CustomRepo and then write SQL and fire query using Hibernate Entity Manager
Now what will be performance in all four cases?
I mean which method is most optimized and which is least and reason?
Related
I need to know what happens when i would run update on db without change actually executing query on table.
I am using spring boot, jpa and db is postgresql.
Any ideas?
I don't have idea how can i do that
I have my django app running on server 1 which is connected to Amazon RDS (PostgreSQL) present on server2. On a day-to-day basis, I have to interact with database often to write/fetch/query data.
Currently, I am following the django ORM way across the app. I just wanted to know if there would be any improvement in the performance if I use PostgreSQL raw sql quereis using django.db connection cursor over ORM?
Following are the proposed ways for one sample query.
Django ORM
table_name.objects().all()
PostgreSQL raw sql quereis using django.db connection cursor
Can someone please suggest which one of the above will lead to a faster increased in performance provided I have my database running on RDS in another server
Using a raw query will result in close to no performance difference. The ORM indeed uses a few cycles to construct the query, but that is insignificant compared to the work of sending the query, the database receiving, interpreting and running the query, and sending the results back.
In some cases the ORM might indeed make a (over)complicated query, but that is not the case if you fetch all records. It sometimes requires ORM expertise (just like it requires expertise in SQL) to find a query that performs better.
You can furthermore already let the Django ORM do the work for you by using .values() to make it more convenient to construct a DataFrame:
res = pd.DataFrame(table_name.objects.values())
I have native query stored in one of the tables and would like to fire the query. I have been looking for alternatives for Pure JDBC. my application has JPA capabilities.
Is there any framework or pattern to fire dynamic native queries?
I want to leverage get_lock() function of mysql as a global lock, but it looks like impossible as I also use JPA as my database layer. Because get_lock() is connection based that means you have to lock/unlock using the same connection, however, there is no native way to retrieve a JDBC connection from JPA. Does that mean get_lock()/release_lock() is totally impossible in JPA?
I don't like unwrap to underlying JPA implementation as it's not portable.
I finally solved this issue by using a JDBC datasource as well as JPA
In the application I'm developing, I am using NHibernate as ORM.
My app has to support SQL Server, and MS Access (I'm using the NHibernate JetDriver).
Now, the thing is that I have a certain query which I cannot achieve using HQL or the ICriteria API; so, I'm using an ISQLQuery for that one.
Now, what bothers me, is that it seems that NHibernate is parsing the native SQL query as well, and thereby changing the SQL code of that query.
It seems that the specific Driver implementation is called, and my query is parsed; and in the case of the JetDRiver, the query is being modified by NHibernate which results in a query that is unexecutable.
So, why is it that NHibernate changes my native SQL queries ?
NHibernate does some changes even in native queries in order to be able to map the entities correctly.
My suggestion... download the JetDriver source from https://nhcontrib.svn.sourceforge.net/svnroot/nhcontrib/trunk/src/NHibernate.JetDriver/ and debug to see what's being broken. It might be a bug there.