How do I create a temporary database for PostgreSQL using initdb? Also, how do I populate it with dummy data and how do I delete it after usage?
I have an entire schema of the database. I don't want to create temporary tables one by one. Using initdb, I would like to be able to give the schema and get a database with the tables, etcetera created.
This is for running integration tests of a spring boot application. I use mybatis to access the database.
Can I use any other tool like arquillian?
There's a workaround this, just change the data directory to a RAM file system, like this once you restart your computer, the data is gone. better you won't change anything in your scripts.
Related
Is there any way to automatically create database functions using jpa/hibernate when i use spring.jpa.hibernate.ddl-auto=create ?
I've a number of custom functions (defined in a separated script file in the project) I use on my custom #Query in my repositories, but those functions needed to be create manually
You might think "what is the problem just run the script after created the database" but this must be done for every environment of the system: dev, test, prod... also it makes impossible to automatically test using in memory database (since when i hit run junit creates the database, hibernate creates the tables in the database, but nobody creates the functions so the repository wont work properly)
So how can I automatically create custom database functions using jpa/hibernate
You can add an import.sql file in your classpath.
Hibernate will create the schema and then run it on the selected db.
You can find more details in the documentation.
Note though that the main purpose for schema generation in Hibernate is prototyping or testing.
I am trying to create a local project for my learning purpose in which I am using h2 as in-memory database.
I am using spring-jpa for my project.
I was wondering is there any way we can take dump of data or writing logs (in this case queries) in a file.
Why do I need this?
so, as h2 is an in-memory database, whenever project ends it deletes all the data.
what I want to get all the data when I re-run the process again.
Tried on searching on internet couldn't find anything.
Instead of using H2, which is solely in-memory, consider using SQLite, which can create a file and will be left behind after the application is terminated.
H2 is not an in-memory database system, H2 supports both persistent and in-memory databases. If you need to preserve your data, use file-based database with jdbc:h2:./somename URL, where ./somename is relative (must starts with ./) or absolute path to the database file without extension.
https://www.h2database.com/html/features.html#database_url
Of course, you can export your data into external file even if you use an in-memory database with SCRIPT TO 'filename.sql' command of H2, but there are no good reasons to use that functionality together with in-memory database instead of persistent one. Such dumps are usually used for migration.
Bonjour,
I am working on changing me Java application from using postgres to an embedded database. I would like the application to deploy with an initial set of data in the database. In the past during installation I have executed an sql script to fully generate the schema and insert the data in to my tables.
Ideally (becasue I don't really want to work out how to connect to the embedded database to generate it) I want to let JPA create my schema for the first time, and when it does I then want to be able to run my SQL to insert the data.
My search has turned up the obvious hibernate and JPA properties that allow running of an SQL script.
Firstly I found when using "hibernate.hbm2ddl.auto" you can define an import.sql file this made me very happy for a day until I realised it only works with create and not with update. My application when using postgres had this set to update. And what i would really like is for it to know if it's had to create the schema and if it has then run the import.sql. No Joy though.
I then moved on to using "javax.persistence.schema-generation.database.action" set to "create" I figured using the JPA specification was probably wiser anyway and so I defined "javax.persistence.sql-load-script-source" the spec says for "create"
The provider will create the database artifacts on application
deployment. The artifacts will remain unchanged after application
redeployment.
This lead me to believe it would do exactly what I wanted, only create the tables "on application deployment" however when I ran my tests using this, each test (creating a new spring context) tried to just create all the tables again and obviously failed, which made me realise application deployment didn't mean what i thought it meant (wishful thinking) and now I realise that JPA doesn't seem to even have an equivalent of Hibernates "update" property, so it's always going to generate the tables?
What I want is to have my tables and data generated when you first spin up the app and for subsequent executions to know the data is there and use it, I am assuming it's too much to hope for that this exists, but i'm sure that this must be a common requirement? So my question is what is the general recommended way to achieve the goal of allowing JPA to create my schema but being able to insert some data in to a db that persists between executions?
The answer is flyway. It is a database migration library, and if you are using Spring boot it is seamlessly integrated, with regular Spring you have to create a bean, which get a reference to the connection pool, creates a connection and does the migration.
Flyway creates a table so it keeps track of which scripts has already been applied to the database, and the scripts are simply part of the resources.
We normally use JPA to generate the initial script. This script becomes V1__initial.sql, if we need to add some data we can add V2__addUsers.sql and V3__addCustomers.sql etc.
Later when we need to rename columns or add additional tables, we simply add new scripts as part of the War file, and when the application is loaded Flyway looks at it's internal table, to see the current version, and then applies any new scripts to bring it up to de desired version.
In Spring the code would look like this
private void performFlywayMigration(DataSource dataSource) {
Flyway flyway = new Flyway();
flyway.setLocations("db/migration");
flyway.setDataSource(dataSource);
log.debug("Starting database migration.");
flyway.migrate();
log.debug("Database migration completed.");
MigrationInfo current = flyway.info().current();
if (current.getState() == MigrationState.FUTURE_SUCCESS) {
log.warn("The Database schema is version " + current.getVersion() + ", this application expects version " + flyway.getBaselineVersion().getVersion());
}
}
In general you should not JPA to create tables directly. because you sometimes need to modify the scripts, for instance on Sybase Varchar(255) means 255 bytes, so if you are storing 2 or 3 byte Unicode chars, you need more space - JPA implementation does not account for that (last time I checked).
I have created some mysql databases in mysql.
Now I am trying to get them into my web application by using the play framework.
I added the mysql configs in the application.conf, added the dependency for the mysql driver in the build.sbt, created my first model and added the models packages as the ebean default in the application.conf.
Now when I go into my browser I get this error:
I`m a little confused right now, because I do not want to create a new table, but use the one I created already.
Any idea what I am doing wrong??
Play's default behaviour during development is to manage your database via the evolutions plugin. You define your initial schema in conf/evolutions/default/1.sql and then apply subsequent modifications in 2.sql, 3.sql etc etc. Whenever there are changes to these evolution files the plugin will attempt to run these on the database, which is what you're seeing here (although it looks like an error, it's really just trying to be helpful.)
If you want to manage the schema yourself (and you probably should on a production DB, for example) add evolutionplugin=disabled to the application.conf file.
I'm using H2 with Hibernate to generate in-memory DB on the fly for unit-testing.
I managed to create the DB successfully, and everything is working ok.
But I have an issue I don't know how to approach.
I need to load reference data to the DB for testing prior to the execution of the tests.
I have this data sored as a SQL insert's file which I need to run only once in real time envirnemnt, however, because the DB is generated every time from scratch I need to figure out how to insert the data on runtime.
The data is quite simple, it's countries lists, states list, etc.
Whats the best way to do it ?
btw, everything is working underneath Spring framework.
For your tests you could execute an init script on creation of the connection.
http://www.h2database.com/html/features.html#execute_sql_on_connection
From the question tags I see you're using Hibernate. You can add a file named "import.sql" to your classpath (i.e. in src/main/resources if you're using a Maven project layout).
From Spring documentation
In addition, a file named import.sql in the root of the classpath will
be executed on startup if Hibernate creates the schema from scratch
(that is if the ddl-auto property is set to create or create-drop).
This can be useful for demos and for testing if you are careful, but
probably not something you want to be on the classpath in production.
It is a Hibernate feature (nothing to do with Spring).