Update deprecated resources

Migrate from resources that have been deprecated or renamed without destroying existing resources.

tip

Backup your Terraform state file terraform.tfstate to use in the case of a rollback.

In the following example, the aiven_database field is migrated to the new aiven_pg_database field for an Aiven for PostgreSQL® service.

Replace references to the deprecated field with the new field. In the following file aiven_database was replaced with aiven_pg_database:

- resource "aiven_database" "mydatabase" {
    project       = aiven_project.myproject.project
    service_name  = aiven_pg.mypg.service_name
    database_name = "<DATABASE_NAME>"
}


+ resource "aiven_pg_database" "mydatabase" {
    project       = aiven_project.myproject.project
    service_name  = aiven_pg.mypg.service_name
    database_name = "<DATABASE_NAME>"
}

List of all resources in the state file:
```
terraform state list
```
Remove the resource from the control of Terraform:
```
terraform state rm <DEPRECATED_RESOURCE>
```
tip
Use the -dry-run flag to preview the changes without applying them.
Add the resource back to Terraform by importing it as a new resource:
```
terraform import <NEW_RESOURCE> project_name/service_name/db_name
```
Check that the import is going to run as you expect:
```
terraform plan
```
Apply the new configuration:
```
terraform apply
```