I have some dictionary table in my DB schema. E.g. "EventType" whth fields "id" and "value".
This table have one row:
1 TypeOne
Can I create a prisma migration with sql?
INSERT INTO "EventType" (id, value) VALUES (2, 'TypeTwo')
All the prisma migration files are valid SQL so you can put any arbitrary SQL in your migration files and it will be added to your migration history.
This is what you have to do:
Generate a new migration without applying it to the database with the --create-only flag.
npx prisma migrate dev --create-only
Take a look at the generated migration.sql file and update it accordingly to add any new SQL statements.
Apply the migrations npx prisma migrate dev
Important Note: Always make sure you apply the changes to migration.sql before applying it to your database. Modifying an already applied migration file will lead to a corrupt migration history.
Related
I have a PostgreSQL db that is used by a Nest.Js / Prisma app.
We changed the name of a field in the Prisma schema and added a new field.
Now, when we want to update the PostreSQL structure, I'm running, as suggested by Prisma, the following commands:
npx prisma generate
and then
npx prisma migrate dev --name textSettings-added --create-only
The idea is to use the --create-only flag to review the migration before it is actually made.
However, when I run it I get a list of the changes to be made to the DB and the following message:
We need to reset the PostgreSQL database "my_database" at "my_db_name#cluster.us-east-1.rds.amazonaws.com:5432".
Do you want to continue? All data will be lost.
Of course I choose not to continue, because I don't want to lose the data. Upon inspection I see that the migration file actually contains DROP TABLE for the tables that I simply wanted to modify. How to avoid that?
So how do I run the update without affecting the data?
UPDATE:
I saw that running with --create-only creates a migration which can then be implemented on the DB level using prisma migrate dev, however, in that migration file there are still some commands that drop my previous tables because of some new parameters inside. How can I run prisma migration without deleting my PostgreSQL data?
UPDATE 2:
I don't want Prisma to drop my tables when I just updated them. The migration file generated, however, drops them and then alters them. Do you know what's the best procedure to avoid this drop? I saw somewhere I could first manually update the DB with the new options and then run the migration, so Prisma can find a way to update it, but that seems too manual to me... Maybe some other ideas?
For some cases like renaming tables or columns, Prisma's generated migration files need to be updated if they already contain data.
If that applies to your use case, Prisma's docs suggest to:
Make updates to the prisma schema
Create migration file without applying it (--create-only flag)
Update the migration script to remove the drops and instead write your custom query (e.g. RENAME <table_name> TO <new_name>)
Save and apply the migration (npx prisma migrate dev)
Note that those changes can lead to downtime (renaming a field or model), for which they have outlined the expand and contract pattern.
It might be a Prisma bug: https://github.com/prisma/prisma/issues/8053
I also recently had this situation. It probably should not try to run migration if you only want to create migration file.
But overall it is expected with Prisma to recreate your db sometimes. If you migration is breaking then it will be required to reset the data anyway when you apply it.
I suggest you to create some seeding script so you could consistently re-create the database state, it's very useful for your development environment.
More info
After removing a column from schema.prisma, and running npm prisma db push, I'm getting the error...
Error: The object 'users_role_df' is dependent on column 'role'.
I'm using Prisma 3.3.0 with the sqlserver connection.
The model looks like this...
model User {
id ....
name ...
role String #default("USER")
}
I see the initial push created the CONSTRAINT users_role_df but now when I remove it from the model, and run push, it's not handling removing the constraint first and then the column.
How can I fix this?
You could try running the command npx prisma migrate dev --create-only to see what the generated SQL looks like for the migration.
You could manually add a DROP CONSTRAINT users_role_df; inside the generated migration or change the order of the SQL commands (if such a command already exists in the generated migration).
It is fine for you to make changes to the migration file as long as you do it before applying the migration to your database.
I'm new to Prisma ORM, & I'm trying to make migrations in Prisma
I see that I way to do this is to update data.model & then just run:
prisma deploy
But what if I want to create a migrations for specific versions of app how could I do that ??
As the prisma documentation describes there are two ways of doing database migrations in prisma:
Using the Prisma CLI
Performing a manual DB migration with plain SQL
If you follow the first approach and edit your data model the changes will be carried out automagically once you run prisma deploy. You can specify the service and stage this will be rolled out to via the PRISMA_ENDPOINT environment variable:
PRISMA_ENDPOINT="http://localhost:4466/{SERVICE}/{STAGE}"
This way you can roll out and test you data model changes in a different stage or on a different service.
The second approach is to manually change the database model via plain SQL. Be careful to ensure the database schema and your data model are in sync.
For more information check out:
https://www.prisma.io/docs/datamodel-and-migrations/migrations-POSTGRES-asd4/
I have created a Postgresql database A using liquibase changesets. Now, I'm creating an application that allows creating a new database B and copies the schema from database A in real-time including the liquibase changesets as the database can still be updated later. Note that at the time of the copied schema in database A could already be updated, making the base changesets outdated.
My main question would be:
How to copy PostgreSQL schema x from database a (dynamically generated at run-time) to b using liquibase? Database b could be on another server.
If it's not possible with liquibase, what other tools or approaches would make this possible?
--
Let me add more context:
We initialize a new database a schema using liquibase changeset.
We can add a new table and field to the database an at run-time. Or during the time when the application is running. For example, we add a new table people to the schema of database a, which is not originally in the changeset. This is done using liquibase classes too. So changeset is added to databasechangelog table.
Now, we create a new database b.
We want to import the schema of the database a to b, with people table.
I hope that is clear.
Thanks.
All schema changes must be run through your schema migration tool
The point of using a database schema migration tool such as Liquibase or Flyway is to have a “single source of truth” regarding the structure of your database tables. Your set of Liquibase changesets (or Flyway scripts) is supposed to be that single source of truth for your database.
If you are altering the structure of you database at runtime, such as adding a table named people, outside the scope of your migration tool, well, then you have violated the rules of the game. You will have defeated the purpose of using a schema migration tool. The intention of using a schema migration tool is that you make all schema changes through that tool.
If you need to add a table while running in production, you should be dropping the physical file for the Liquibase changeset (or Flyway script) into the file system of your database server environment, and then invoking Liquibase (or Flyway) to run a migration.
Perhaps you have been misunderstanding the sequence of events:
If you have built a database on server "A", that means you installed Postgres, created an empty database, then installed the collection of Liquibase changesets you have carefully built, then ran a Liquibase migration operation on that server.
When you go to create a database on server "B", you should be following the same steps: Install Postgres, create an empty database, installing the very same collection of Liquibase changesets, and then running a Liquibase migration operation.
Alternatively, if making a copy of server "A" to create server "B", that copy should include the exact same Liquibase changesets. So at the end of your copy process, the two databases+changesets are identical.
Here's how I solved this problem of mine using the Liquibase Java library:
1.) Export the changelog from the source database into a temporary file (XML).
Liquibase liquibase = new Liquibase(liquibaseOutFile.getAbsolutePath(), new FileSystemResourceAccessor(), sourceDatabase);
liquibase.generateChangeLog(catalogAndSchema, changeLogWriter, new PrintStream(liquibaseOutFile.getAbsolutePath()), null);
2.) Execute the temporary file to the new data source.
Liquibase targetLiquibase = new Liquibase(liquibaseOutFile.getAbsolutePath(), new FileSystemResourceAccessor(), targetDatabase);
Contexts context = new Contexts();
targetLiquibase.update(context);
Here's the complete code: https://czetsuya-tech.blogspot.com/2019/12/generate-postgresql-schema-using-java.html
I am working on a web project using ASP.Net 5 and EF7.
I have imported all the tables from existing database onto my models in my project. However, I am having problems in regards with migrations.
I have created the initial migration, made some changes on particular entity, create another migration following the changes I have made and now want to apply the changes on the database.
After running this command below:
dnx ef database update [Migration]
the dnx is trying to apply the 'initial' migration with all the entities which are already in database and this causes an error as below:
{ There is already an object named ['EntityName'] in the database. }
Can you please advise on how to do the migration on the existing database?
Thanks
Saeed
In EF6 you would run a migration with the -IgnoreChanges flag and it would take a snapshot of the model without any Up() code. This is missing from EF 7(EF Core) as indicated here.
The workaround for now is delete or comment out the code for existing database objects from the Up() code of the migration and then update-database. Subsequent migrations will then include only the changes.
After 2 days I found a way for EFCore that is not in google and internet!
How My steps works?
When you have a database with 10 table and you have data in tabales that you don't want to clear's data.and after this you will create new models in your code first and runnig to existing database and you will get error "Invalid object name 'tableName'." for query to new tables and you want to create migrations and do update it to existing database but first migration will create all queries for old and new tables if you run update-database you will get "There is already an object named ['EntityName'] in the database." for your initial migration.
How fix it?
Delete all migrations and snapshot in you database project
Delete __EFMigrationsHistory table in your existing database (if exist)
Run in Package manager console:
Note before run: This code will create new context and models of your existing database to Data folder so don't forgot to check you have not Data folder in your project.
Scaffold-DbContext "your connection string"
Microsoft.EntityFrameworkCore.SqlServer -OutputDir Data
Run in Package manager console:
Note before run: Create first migration for initial database with Data folder context (OldDataBaseContext is inside of your Data folder that created by step 2)
Add-Migration initial -Context OldDataBaseContext
Delete all code in Up method inside of created initial migaration in step 3
Run in Package manager console:
Note before run: Update databse with Data folder context (OldDataBaseContext is inside of your Data folder that created by step 2)
Update-Database -Context OldDataBaseContext
Delete data folder that created in Step 2
Go to snapshot and initial migration classes and change the deleted context from Data folder to main context that is exist in your database project (just fix it for build)
Run:
Note before run: Add migration for main context that have new database changes
Add-Migration newUpdate
Run:
Update-Database
I Hope this help someone.
If you are strongly believe, that new (EF7) database schema will match your old database schema (including index and key names) - you may run 'Initial' migration to empty (temporary) database and then copy __EFMigrationHistory table from there to your real database.
Otherwise, I recommend you create empty database using migration and use sql insert into ... select commands to copy data from your old database. Without this, you will receive exceptions when upgrading database later - for example changing index will lead to DropIndex and CreateIndex migration commands, and DropIndex will fail because there is no index with this name (index exist with other, pre-EF7 name).
In my projects - old (from EF6) and new database schemes are different, and I used second option.