In my project, current approach is to create database if not already exists using CreateDatabaseIfNotExists and doing seeding initial data from that Intializer as well. I also added Code First Migration support after upgrade to Entity 4.4, so that in the future when we change the modle/database structure we can update client side database without drop their exist database.
However it didn't seems to working well, for example, I am now stuck on design time where forms wouldn't load and the error message is something like The model backing the 'myEntities' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269).. But the model and database is indeed the updated version, just seems Migration didn't recognize the database generated by CreateDatabaseIfNotExists, but at the same time all seems working well at run time.
Also after that I noticed that if I let CreateDatabaseIfNotExists initialize a database, Add-migration afterwards will fail and complain that pending migration and ask me to do a update-database. When I try to do a the update-database, it will fail as well because the migration path seems assume the database is in initial setup state and will trying to running all the migration scripts while none should be run as the database generated by CreateDatabaseIfNotExists is indeed sync with current model and should not be migrated at all.
I discovered that there is a MigrationHistory table in System Tables, that table will always save the database initialize history regardless of whether the initializer is CreateDatabaseIfNotExists or MigrateDatabaseToLatestVersion. The difference is that if database is initialized by CreateDatabaseIfNotExists1, everytime the database initialized, the migriationId for that initialize record will be different, butMigrateDatabaseToLatestVersion` will always save same set of migrationId for each of the Migration steps. I guess that is how Entity Framework 5.0 works.
So in the end, I give up and rewrite my DB Access code to seeding the initial database data
in other part of my code rather than the CreateDatabaseIfNotExists or MigrationsConfiguration` class because either suit my need.
Related
I am not clear how the executeAsync works in Camunda 7.15.0 version.
Using Java code in spring-boot application, I am trying to migrate few process instances from one process version to another using migration plan.
In java code when I use execute() method then the code is obviously executed immediately.
import org.camunda.bpm.engine.RuntimeService;
final MigrationPlan migrationPlan = runtimeService.createMigrationPlan(fromProcessDefinitionId, toProcessDefinitionId).mapEqualActivities().build();
final ProcessInstanceQuery processQuery = runtimeService.createProcessInstanceQuery().processDefinitionId(fromProcessDefinitionId);
runtimeService.newMigration(migrationPlan).processInstanceQuery(processQuery).executeAsync();
But When I use executeAsync() method then I see the batch job waiting in the batches section but does not complete. How to know when will it execute?
Issue can be recreated in https://github.com/firstpostt/camunda-demo-migration. It needs postgres database and credentials need to be given in application.yml
There is an entry in act_ru_batch table. I don't see any entry in act_ru_job table
Can I configure in bpm-platform.xml file to make sure my migration plan runs within next 15 minutes when I use executeAsync() method?
Is there any option to force-trigger the batch from the admin cockpit when needed?
Found the problem. The issue was with Postgres database but I am not sure what is the exact root cause because the issue is not easy to recreate. I dropped the database and created it again from scratch which seems to resolve the issue (I used the same sql scripts again using flyway so nothing changed w.r.t database schema. The only difference I can think of is that after some data is populated already into the tables then I created the unique constraint on camunda tables which might have caused the issue. Now I created unique constraint immediately before populating any data into the tables)
P.S:
I was using unique constraint in postgres Database https://docs.camunda.org/manual/7.5/user-guide/process-engine/database/#additional-database-schema-configuration
I figured out that the issue was with database because I tried with h2 filesystem database(camunda.bpm.database.schema-update as true and spring.datasource.url=jdbc:h2:~/camunda;DB_CLOSE_ON_EXIT=false) and batch worked fine.
Then I used postgres database (without the unique constraint script) and batch worked fine. When I created a new database schema with the unique constraint script then the batch did not work and even if I dropped the constraint the batch did not work anymore
So I dropped the database and created a new database again without unique constraint and then the batch worked fine. After that I added the unique constraint and the batch still works fine.
I am not able to recreate the issue consistently but my guess is that it has something to do with the unique constraint. If you are not using this unique constraint then I am sure that this problem will never occur at all
In my Spring-Boot project when:
javers.sqlSchemaManagementEnabled=true
The Javers tables are created on the first execution (when the tables do not exist on the database) and the code runs as expected, however from the second execution onwards an exception is thrown describing that the tables cannot be created because them already exist. This is the situation that I cannot understand, isn't Javers supposed to know that the tables already exist and do not attempt to create the tables?
javers.sqlSchemaManagementEnabled=false
If the tables where already created on the database, manually or executing the application with this option as 'true' at least once, the application executes as expected.
What am I supposed to do?
Is there something wrong with my Spring-Boot configuration? The application was supposed to run with 'sqlSchemaManagementEnabled=true' even with the tables already created?
I expected is to leave the 'sqlSchemaManagementEnabled=false' and create the tables manually?
I had the same problem, when using other than public schema in PostgreSQL.
I solved it by switching to public schema, now it works correctly with javers.sqlSchemaManagementEnabled=true.
For other schemas, you should somehow specify the schema name in org.javers.repository.sql.schema.TableNameProvider
If javers.sqlSchemaManagementEnabled=true, Javers creates SQL tables if they do not exists already.
It's checked here:
https://github.com/javers/javers/blob/master/javers-persistence-sql/src/main/java/org/javers/repository/sql/schema/JaversSchemaManager.java#L215
It's hard to say why it doesn't work in your case, try to debug this code using the latest Javers version.
We are looking to implement Continuous Integration using Circle CI but we are not sure on how should we proceed with our test database. We have the following alternatives in mind:
Run the migrations from scratch (the problem is that we have a lot of migration files, our first migrations were moving everything from MySQL and PostgreSQL and using a legacy database, so, it's rather complex).
Recreate the current DB and have a .sql file that will create our current tables, and then, we create a seeder to fill the information that we need.
But we are not sure which is the best alternative or if we're missing something?
Thank you
I am new to using Laravel, and I'm currently learning about Laravel's database migration and seeding features.
It's working with the command prompt, but I can migrate and seed in phpMyAdmin as well. What are the advantages and disadvantages of migrating and seeding within Laravel as opposed to phpMyAdmin?
From Laravel docs on Migrations & Seeding:
Migrations are a type of version control for your database. They allow a team to modify the database schema and stay up to date on the current schema state.
A simple search for why database migration also gives me some pretty decent results. One of the easiest to understand is a page by FlywayDB (I have no idea who they are until I search this term up):
Database migrations are a great way to regain control of this mess. They allow you to:
Recreate a database from scratch
Make it clear at all times what state a database is in
Migrate in a deterministic way from your current version of the database to a newer one
The illustration they made perhaps explain it more clearly, so you may want to check it out.
I have a local instance of a database that I recently created using DbContext.Database.Create(), so the __MigrationHistory table exists with an InitalCreate entry that matches the code at the moment.
Some code-based migrations exist in the Migrations folder, however. These will be run in our development and staging environments to bring those databases in line with the code. I don't need to apply them locally, however, since I created the database using the current code.
I now need to make a change to the model and create the corresponding migration. But when I run Add-Migration TestMigration, I get the following error
Unable to generate an explicit migration because the following explicit
migrations are pending:
[201203271113060_AddTableX,
201203290856574_AlterColumnY]
Apply the pending explicit migrations before attempting to generate
a new explicit migration.
What should I do in this case? I can't point the Add-Migration tool at another environment because it's not guaranteed that version matches what I have locally. I want a migration that matches only the changes I've made.
It seems I have a few options but none are ideal:
Delete the other migrations from the Migrations folder, run the Add-Migration command, upgrade the database, then restore the old migrations. This is simple but seems a bit hackish.
Revert to the version of the model in source control that the first migration was applied to, then build this and use it to create the database. Then get the latest version, apply all the migrations, then I'm ready to add my migration. This seems like a lot of effort!
Create the migration manually.
Does anyone have any suggestions about how to manage this?
We are planning to use a variant of your Option #1...
Our Standard Operating Procedure is to generate a SQL script for each migration (using the -script option of update-database), in order to have SQL scripts to be applied to end-user "production" databases by InstallShield (we plan to use EF update-database only for developer databases).
Thus, we have both the Migration .cs files and the corresponding .sql files for all migrations in our Migrations folder.
So rather than deleting the migrations from the Migrations folder (as you proposed in #1), we use SQL Mgmt Studio to manually apply just the parts of the .sql files that do the inserts into _MigrationHistory.
That brings the _MigrationHistory of the local database up-to-date with the changes that are already incorporated into that database.
But it's a kludge, and we're still looking for a better solution.
DadCat
What I've found works best is very simple: don't use DbContext.Database.Create() once you've enabled migrations. If you want to programmatically create a new database, use the migrations API instead.
var migrator = new DbMigrator(new Configuration());
migrator.Update();
Then you've got the full migration history and adding further migrations works just as expected.
You either need to run "update-database" from the package manager console to push your changes to the database OR you can delete the pending migration file ([201203271113060_AddTableX]) from your Migrations folder and then re-run "add-migration" to create a brand new migration based off of your edits.
I have encountered the same problem.
If you run
Update-database
and then run
Add-Migration YourMigrationName
This solves the problem
simply exclude the old migration file from the solution files.