I need a why to change the JPA catalog element in my java class? We have many database environments which we need to be able to deploy our application too. Example: In your dev environment we have a database for new development, and production support. All database live on the same server so we have the following database names: am_web_dd and am_web_ps. So we need to be able to change the catalog at build time or start up time. We've thought of using Maven to do a search and replace during build but I was wondering if there is a way of doing this with a parameter?
Here is one of our #RooJpaActiceRecord statements:
#RooJpaActiveRecord(catalog = "am_web_t4", schema = "dbo", table = "user_t")
I would like to be able to make catalog a parameter. Is this possible? if not what would be the best approach?
Thank you for your time!
I know it is possible from a JPA standpoint, but I don't think you will be able to using straight Roo. This might help.
There may also be a way to use a Java Configuration object in Spring to build your JPA Entity Manager. I think that's were you want to set it.
The approach you suggest of making catalog dynamic would be suitable if you wanted to let the user choose/change the schema on demand, however, it looks like this is not your requirements, so I would steer away from this path as it more difficult than you need.
You can use spring profiles to define different database connections and use an environment variable to define which one is active. Spring profiles can be set in XML or java configuration classes.
Related
In My Application, Using the below technologies
Spring boot 2.7.x
Cassandra
spring batch 5. x
java 11
As part of this, I need to extract data from the Cassandra database and need to write out the file
so here I need to use queries to fetch data so
just want to know what is the best way to maintain all queries at one place so any query changes come in the future, I shouldn't build the app rather just need to modify the query.
Using a repository class is necessary. If you are using JPA i recommend using a repository for each Entity class. With JDBC it is possible to create a single repository which contains all the queries. To access the query methodes i would use a service class. In this way your code is structured well and maintainable for future changes.
We are working on a spring boot library to generate and validate OTP. It uses database to store the OTP.
We are using Spring Data JPA for Database operations, as it will be easy to handle multiple database systems according to the project.
Now we have ran in to a problem, most of our projects uses Oracle with a single database.
When using the the same lib in multiple projects there is a name conflict.
So we want the name of the OTP table to be configurable using a property file.
We tried #Table(name = "${otp-table-name}") But its not working.
We did a lots of research and found out the hibernate naming strategy configuration can help.
But we dont want to use lots of configuration in our library as we need the library to be easily usable in the projects.
Can someone help us on this aspect.
Thanks in advance.
You can dynamically determine the actual DataSource based on the current context, use Spring's AbstractRoutingDataSource class. You could write your own version of this class and configure it to use a different data source based on the property file.
This allows you to switch between databases or schema without having to change the code in your library.
See: https://www.baeldung.com/spring-abstract-routing-data-source
Using a NamingStrategy is good approach.
You could let it delegate to an existing NamingStrategy and add a prefix.
Use a library specific default for the prefix, but also allow users of your library specify an alternative prefix.
This way your library can be used without extra configuration, but can also handle the case of multiple applications using it in the same database schema.
Of course this might involve the risk of someone using the default prefix without realizing that, that is already used.
It is not clear what the consequences of that scenario are.
If the consequences are really bad you should drop the default value and require that a project specific prefix is used.
When no prefix is specified throw an exception with an instructional error message telling the user, i.e. the developer how to pick a prefix and where to put it.
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/
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.
I have a requirement to load properties for different environments like DEV, QA and I have different properties file for each environment. So I solved this by setting environment property in server and accessing this value to load respective property files. When googled I found that Spring Environment Profiles provides the solution for similar scenarios. However, even here I have to set active-profile variable in server as environment variable.
What are the benefits of using Spring Environment Profiles over my native approach?
Profile lets you override anything in the Spring Context, properties, beans etc, from environment to environment, customer to customer. It is a easy and clean way to have custom implementations at any level of your beans.
For example, Lets assume your are building a product which read data from a relational database, you can develop DAO layer with profile="default". Then if another customer of yours or you yourself want to provide NoSQL support, you can develop another DAO layer with profile="nosql". This will make sure you can same product on both support based on profile. Easy and clean.
I am working on a project which have profile="local" which will help you bring application locally with out any database dependency (kind of mock mode). You can think of million other applications like to make use of Profile concept.