Is there a way to export database schema from Loopback 4 models.
When you execute npm run migrate it can alter the database, but I can't find a way to export the SQL script to generate the database structure.
Thanks for any help
Hi from the LoopBack team.
We currently don't support generating the scripts to generate the database structure, though it's a good idea. This GitHub issue: https://github.com/strongloop/loopback-next/issues/4757 tracks the feature request.
Related
I would like to unit test CRUD operations against a pre-populated Neo4j database.
I am thinking that a way to do this might be to:
Create a an empty database (let's call it testDB)
Create a database backup (let's call it testingBackup)
On running tests:
Delete any data from testDB
Populate testDB from testingBackup
Run unit test queries on the now populated testDB
I am aware of the backup / restore functions, the load / dump functions and the export to csv / load from csv etc. However, I'm not sure which of these will be most appropriate to use and can be automated most easily. I'm on Ubuntu and using python.
I would need to be able to quickly and easily alter the backup data as the application evolves.
What is the best approach for this please?
I have something dome somthing similar, with some caveats. I have done tests like these using Java and testcontainers. Also, i didn't use neo4j. I have used postgress, sqlserver and mongodb for my tests. Using the same technique for neo4j should be similar to one of those. I will post the link to my github examples for mongodb/springboot/java. Take a look.
The idea is to spin up a testcontainer from the test (ie, a docker container for tests), populate it with data , make the application use this for its database use, then assert at the end.
In your example, there is no testingbackup. Only a csv file with data.
-Your test spins up a testcontainer with neo4j from your test (this is your testdb).
-Load the csv into this container.
-get the ip, port, user, password of the testcontainer (this part depends on the type of database image available for testcontainers. Some images allow you to set your own port, userid and password. Some of them won't.)
-pass these details to your application and start it (i am not sure how this part will work for a python app. here you are on your own. See the link to a blog i found for a python/testcontainer example below. I have used spring-boot app. You can see my code in github)
-once done, execute queries to your containerized neo4j and assert.
-when the test ends, the container is disposed off with the data.
-any change is done to the csv file which can create new scenarios for your test.
-create another csv file/test as needed.
Here are the links,
https://www.testcontainers.org/
testcontainers neo4j module https://www.testcontainers.org/modules/databases/neo4j/
A blog detailing testcontainers and python.
https://medium.com/swlh/testcontainers-in-python-testing-docker-dependent-python-apps-bd34935f55b5
My github link to a mongodb/springboot and sqlserver/springboot examples.
One of these days i will add a neo4j sample as well.
https://github.com/snarasim123/testcontainers
I'd like to use alembic in offline mode, and execute the SQL migrations from an external software.
The external software tracks the DB version, so I don't need the alembic_version table at all.
Do you know if I can generate SQL migrations without creating an alembic_version table ? Is it a supported feature ?
Thanks
I don't think generating migrations off line is an available feature till now as #zzzeek wrote in 'Writing Migration Scripts to Support Script Generation' section in the official tutorial https://alembic.zzzcomputing.com/en/latest/offline.html . I do hope the new feature will come as my project can't connect to the database server directly but generating sql scripts off line will save my time by preventing writing SQL DDL and SqlAlchemy objects both.
I have an application which use Zend Framework and Doctrine.
I want to change for a module the database from the default settings.
I have created an alternative connection for doctrine.
When creating/updating the tables using,
./vendor/bin/doctrine-module orm:schema-tool:update --force
the tables are created in the first configuration of database.
Basically what I want to update the second configured database tables.
Can someone help me with an working example ?
Thanks,
Bogdan
To my knowledge, the schema-tool binary only works with the orm_default database.
Now, there's certainly nothing stopping you from having modules that add additional named connections. See this documentation for doing that:
https://github.com/doctrine/DoctrineORMModule/blob/master/docs/configuration.md#how-to-use-two-connections
But, the tooling around managing those additional databases might be a little "roll your own". The good news is all the pieces are there (Doctrine's underlying SchemaTool classes), you would just need to wire them up and build a cli command that acts on multiple schemas.
All that being said, if you find yourself using multiple unique schemas in the same database engine (unique being the key word to account for things like doctrine sharding), I worry your application design might be potentially troublesome. It could be possible that your multiple storage domains should actually live as separate applications.
I am building a small financial web app with django. The app requires that the database has a complete history of prices, regardless of whether someone is currently using the app. These prices are freely available online.
The way I am currently handling this is by running simultaneously a separate python script (outside of django) which downloads the price data and records it in the django database using the sqlite3 module.
My plan for deployment is to run the app on an AWS EC2 instance, change the permissions of the folder where the db file resides, and separately run the download script.
Is this a good way to deploy this sort of app? What are the downsides?
Is there a better way to handle the asynchronous downloads and the deployment? (PythonAnywhere?)
You can write the daemon code and follow this approach to push data to DB as soon as you get it from Internet. Since your daemon would be running independently from the Django, you'd need to take care of data synchronisation related issues as well. One possible solution could be to use DateTimeField in your Django model with auto_now_add = True, which will give you idea of time when data was entered in DB. Hope this helps you or someone else looking for similar answer.
I have few questions about this plugin.
1- what does it do?
Is it for exchanging databases between teams or changing their schema or creating tables based on models or something else?
2- if it is not meant to create tables based on models where can I find a script that does this?
3-can it work under windows?
thanks
The Migrations plugin allows versioning of your db changes. Much like is available in other PHP frameworks and Rails.
You essentially start with your original schema and create the initial migration. Each time you make a change you generate a 'diff' that gets stored in the filesystem.
When you run a migration, the database is updated with the changes you made. Think deployment to a staging or production server where you want the structure to be the same as your code is moved from environment to environment.
We are starting to look at this plugin so we can automate our deployments, as the DB changes are done manually right now.