I would like to use liquibase in my spring boot app. My requirement is that I have a dummy schema which is populated with tables every time I change the entity classes. This is done by hibernate's ddl create. There are many identical schemas to the dummy schema with data. I want those schemas to be compared with the dummy schema on update and be synced without affecting my data. How can I achieve this? I could not find a tutorial anywhere. If there is one please do give me the link.
I think this tutorial explains what your are looking for
baeldung maven liquibase plugin
In section 5.3 is a description on how you can get a changlog file with differences between two databases.
Related
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 have a situation where I have two SpringBoot microservices which share the same database schema. The schema is maintained by a liquibase changelog file. One service reads from the database, and the other service is responsible for writing to the database.
Right the Writing Service owns the liquibase changelog file, which means the Writing service owns the schema. And the way I validate the Reading Service is to deploy the Writing service first into a test environment followed by the Reading Service, and then execute end-to-end tests against the Reading Service.
Is there a way for both services (two separate apps, two separate repos) to share the liquibase changelog file? I feel this is similar to a contract test as the changelog file will be the contract for both services, but wasn't sure if there was something provided by Liquibase, Spring, Pact, etc that supported this idea.
Thanks for your time!
I think it won't count as a legit answer, but two solutions come to mind:
since your second service reads from the database, I suppose you have a full set of entities there, and entities are supposed to match your database schema. And since you're using Spring, I suppose you can add spring.jpa.hibernate.ddl-auto=validate to the application.properties file. This will validate your database schema against the entities.
You can create a separate library which will contain all the changeLogs. After that you can include this library to both services, so liquibase will validate that all changeSets are executed during application's deployment. But you should make sure that all your changeSets have preConditions, so your deployment won't fail and there won't be any duplicates in the DB schema.
I'm trying to populate my database with around 150 different values (one for each row).
So far, I've found two different ways to implement the inserts, but none of them seems to be the best way to do it.
Flyway + Postgres: One of them is to create a migration file and make use of the COPY command from postgres but to do so, I need to give superuser permissions to the user and that doesn't seem to be a good choice.
Spring boot: place a data.sql file in the classpath with a lot of inserts. If I'm not wrong I would have to write 150 insert into... statements.
In previous projects, I have used liquibase and it has a loadData command which is very convenient to do what is says it does. You just give the file, table name and that's it. You end up with your csv file values in your table rows.
Is there an alike way to do that in flyway? What is the best way to populate the database?
Actually there is a way, you can find more info on the official documentation's page
You need to add some spring boot properties too:
spring.flyway.enabled=true
spring.flyway.locations=classpath:/db/migration
spring.flyway.schemas=public
Properties details here
In my case, a use Repetables scripts by my needs but take care with the prefixes
Flyway is a direct competitor of liquidbase, so if you need to track the status of migrations, manage distributed migration (many instances of the same service start simultaneously, and only one instance should actually execute a migration), check upon startup which migration should be applied and execute only relevant migrations, and all other benefits that you have previously expected from "migration management system", then you should use Flyway rather than managing SQLs directly.
Spring boot has integrations with both Flyway and Liquidbase, so you can place your migrations in the "resources" folder, define a couple of properties and spring boot will run Flyway automatically.
For example, here you can find a tutorial of Flyway integration with spring boot.
Since flyway's migrations are SQL files- you can place there whatever you want (even plSQL I believe), it will even manage transaction per migration guaranteeing that the migration "atomicity" (all or nothing, no partial migration).
So the straightforward approach would be creating a SQL file file with 150 inserts and running it via flyway in spring or even via maven depending on your actual setup.
If you want more fine-grained control and the SQL is not flexible enough, its possible to implement Migration in Java Code. See Official Flyway Documentation
I have tried the following
liquibase:generateChangeLog - It generated the change log from my db.I need to generate the change-log from my JPA entities.
liquibase:diff - It generates the change log for the difference between my db and JPA entities. I cannot say that my db is always empty and I want to generate the create scripts which can be applied on fresh db.
How can I use Liquibase to generate the scripts based on my JPA entities only ?
Note : I am ok in providing the details about my db such as url,driver etc
If your IDE of choice is IntelliJ IDEA, I'd recommend using the JPA Buddy plugin to do this. It can generate Liquibase changelogs by comparing your Java model to the target DB.
So if your DB is empty, you'll get a changelog that describes your whole model. But it is also useful to keep your evolving model and your changelogs in sync.
Once you have it installed and have Liquibase as your Maven/Gradle dependency, you can generate a changelog like this:
Try to use liquibase-hibernate-plugin
You have to create a schema with persistence properties according to Database Schema Creation and then use the Liquibase generateChangeLog command.
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.