I am creating backend for my CRUD application and I have an existing ORACLE DATABASE. I just want to fetch data from it but I 've seen so many tutorials and in every tutorial they are creating new table in the database by using #table annotation which I don't need ? So if anybody knows about this I could use some of his/her help in this problem?
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I created a spring boot project and I link it with my DB under PgAdmin.
I've modified the application.properties correctly and created a class named "user" and its repository "userRepository" but I don't know if this will automaticly create the user table in the DB (I used annotations) or I have to create it in PgAdmin ?
Do I need to specify any controller or webController if I want to have Crud operations ? And where does the CrudRepository exists do I need to generate it and how ?
Excuse me this my first experience with spring, I will really appreciate if you guys can help me.
Thanks in advance.
For your first question:
I don't know if this will automaticly create the user table in the DB
You have several ways how to create your tables, for example with property in application.properties file
spring.jpa.hibernate.ddl-auto = [none|validate|update|create-drop]
where none means this configuration not affect existing database
update means updating changes in database
create-drop means creating all tables from scratch according your project entities classes.
You can check this documentations for additional information
https://docs.spring.io/spring-boot/docs/1.1.0.M1/reference/html/howto-database-initialization.html
59.2 Initialize a database using Hibernate
also you can check how to initialize database with existing sql scripts files in documentation above
59.3 Initialize a database using Spring JDBC
For question: Do I need to specify any controller or webController if I want to have Crud operations ? And where does the CrudRepository exists do I need to generate it and how ?
Yes you should create controllers to handle requests and repositories to work with JPA.I also suggest check tutorial first, for example this one (first in google)
https://bezkoder.com/spring-boot-jpa-crud-rest-api/
I recentely started using JHipster. I am facing problem while creating new tables (other than the jhipster provided). JHipster provided their tables through 00000000000000_initial_schema.xml even though same table has entity java classes.
But now i have created new #Entity class but tables are not getting created. What changes need to do ?
One more thing to ask, how we can disable initial schema totally and generate tables from Entity classes, even for existing jhi_* tables
Thanks in advance :)
I am trying to solve problem by using properties file but in properties file we can handle only database driver problem.if we want to mysql to oracle database need to change all my query.the problem is now how to make query independent without hibernate api?? please suggest
How can I generate an entity(and a database table) in a different schema other than the default public schema for an existing Jhipster(4.6.2) project generated with spring boot and AngularJS as the technology stack. [Database - Postgresql]
I am very interested if it is possible. Otherwise one simple way to reach that: you could try to generate the entity using the jhipster command jhipster entity <entityName> --[options] see for more details.
And customize your application to use multiple databases by following this excellent article: https://www.baeldung.com/spring-data-jpa-multiple-databases
so im quite new to all spring and hibernate so i used a feature in myeclipse called generate CRUD application (it uses spring and hibernate for the heart of the application and JSF for presentation objects)that im intended to make changes so that i can work with .. my question is the following .. after i made the application that works fine by the way , i discovered that there are fields and probably even tables to be added to the database(an oracle 11g instance database)..so my questions are the following:
if i create the classes and update the existing .. will it be written directly in the database?
if not is there any way to do it because i dont think a direct update in the database will be a good idea ..
thank you in advance ..
If I understand correctly, you want to know whether the database schema can be created/updated automatically from your #Entity classes, and how to enable/disable such creation. Yes, it's possible by using some property. The name of the property would depend on your project kind. For example, in a default Spring Boot application, you can have
spring.jpa.hibernate.ddl-auto: update
in application.properties. The value update above will have the schema automatically created on first run and then updated on subsequently. validate instead of update won't alter the schema, but just validate it.
This stackoverflow post lists the possible values and their behaviour.