How to dry-run sql update query using spring jpa and postgresql - sql

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

Related

Change H2 Database to SQL database in spring boot

I am learning Spring boot by myself. Now I am using H2 database in my spring boot application.
How do I change H2 database to SQL database?
Is there any other application need to install for using SQL database?
No, you just need to add corresponding dependencies with the DB and then update the application.properties file with the new configuration of your desired DB.
Look at this to work with MySQL:
https://mkyong.com/spring-boot/spring-boot-spring-data-jpa-mysql-example/
Or you may want to use different profiles with different DBs (eg: H2 & MySQL)
See this: https://www.baeldung.com/spring-profiles

Execute SQL Procedures in Hive

​Hi,
Below is the scenario we have, please suggest possible solutions,
We have an existing reporting solution (SAP) executing a procedure in RDBMS (using JDBC Connection) to generate reports based on the user input.
Now we are planning to move from RDBMS to hive as our data source.
Is there a way to connect to hive and execute a procedure (HPLSQL or a UDF performing an equivalent job of Oracle procedure) using a JDBC connection?
Or is there any alternate way to run a procedure or a program in hive or spark using jdbc?
Thanks
it is possible to connect to Hive using JDBC
https://cwiki.apache.org/confluence/display/Hive/HiveClient#HiveClient-JDBC
However if your cluster is secured, you will need to connect to HiveServer2
https://cwiki.apache.org/confluence/display/Hive/HiveServer2+Clients#HiveServer2Clients-JDBC
Plus to that, store procedures are supported in Hive from the 2.0.0 version
https://issues.apache.org/jira/browse/HIVE-11055

JPA Hibernate Performance

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?

What is the proper way to add a Trigger to a Oracle11g Database using Jdevelopper 12.1

For a Database class, we have to initiate a bunch of SQL triggers using a Oracle 11g Database in a VM (Virtual Machine).
Problem is, even if we're 99% sure our triggers are properly made, we can't seem to find where to add the triggers from Jdev to our database.
What would be the proper way to insert a trigger in the DB?
Thanks!
You can always use DDL with JDBC. The statement to execute is CREATE TRIGGER ..

Is it possible in Oracle SQLDeveloper to prefetch certain tables’ metadata and keep it cached locally?

I am working on a remote database which has several master tables. the meta-data & the actual data in these tables changes rarely.
When querying DB involving these tables and using certain functions (Ex: ctrl+space to auto-complete a table/column name), it takes too long to query the remote DB to fetch this data since its not cached locally.
Is there any extension/plug-in/configuration in SQLDeveloper to do this.
(Oracle SQLDeveloper Version 1.5.1 Build MAIN-5440)
Try to update to version 2.1
Use a tool like SQuirreL to build your queries and then copy them into SQLDeveloper. SQuirreL caches the metadata.
You could create a view on the local DB, that would keep the metadata local.