Discussion on: How to set up a free PostgreSQL database on Heroku

[Andrew Obrigewitsch]

When I try to connect to a free account with Prisma I get the following errors:

Prisma Migrate could not create the shadow database. Please make sure the database user has permission to create databases. More info: pris.ly/d/migrate-shadow. Original error:
Database error
Error querying the database: db error: ERROR: permission denied to create database
0: sql_migration_connector::flavour::postgres::sql_schema_from_migration_history
at migration-engine/connectors/sql-migration-connector/src/flavour/postgres.rs:279
1: sql_migration_connector::sql_database_migration_inferrer::calculate_drift
at migration-engine/connectors/sql-migration-connector/src/sql_database_migration_inferrer.rs:57
2: migration_core::api::DevDiagnostic
at migration-engine/core/src/api.rs:95

[Nikolas Burk]

Hey Andrew 👋 thanks for the comment! This is likely because Heroku doesn't provide enough access privileges on the PostgreSQL DB server to create the shadow database which is needed during the migration.

You can resolve this by creating a second database by following the instructions in the article once more, and then add the URL of the second DB as the value for the shadowDatabaseURL field on the datasource block as explained here:

datasource db {
  provider          = "postgresql"
  url               = env("DATABASE_URL")
  shadowDatabaseUrl = env("SHADOW_DATABASE_URL")
}