I'm currently using Postgres, you just have to change some lines in the application.yaml:
jpa:
database: postgresql
database-platform: org.hibernate.dialect.PostgreSQL94Dialect
properties:
hibernate:
format_sql: true
show_sql: false
#Hibernate dialect is automatically detected except Postgres and H2.
#If using H2, then supply the value of ca.uhn.fhir.jpa.model.dialect.HapiFhirH2Dialect
# hibernate.dialect: ca.uhn.fhir.jpa.model.dialect.HapiFhirH2Dialect
#If using postgres, then supply the value of ca.uhn.fhir.jpa.model.dialect.HapiFhirPostgresDialect
dialect: ca.uhn.fhir.jpa.model.dialect.HapiFhirPostgresDialect
hbm2ddl:
auto: update
jdbc:
batch_size: 20
Good luck!
Marcelo