Initialize a Database Using Basic SQL Scripts

Spring Boot can automatically create the schema (DDL scripts) of your JDBC DataSource or R2DBC ConnectionFactory and initialize it (DML scripts). It loads SQL from the standard root classpath locations: schema.sql and data.sql, respectively. In addition, Spring Boot processes the schema-${platform}.sql and data-${platform}.sql files (if present), where platform is the value of spring.sql.init.platform. This allows you to switch to database-specific scripts if necessary. For example, you might choose to set it to the vendor name of the database (hsqldb, h2, oracle, mysql, postgresql, and so on). By default, SQL database initialization is only performed when using an embedded in-memory database. To always initialize an SQL database, irrespective of its type, set spring.sql.init.mode to always. Similarly, to disable initialization, set spring.sql.init.mode to never. By default, Spring Boot enables the fail-fast feature of its script-based database initializer. This means that, if the scripts cause exceptions, the application fails to start. You can tune that behavior by setting spring.sql.init.continue-on-error.

Script-based DataSource initialization is performed, by default, before any JPA EntityManagerFactory beans are created. schema.sql can be used to create the schema for JPA-managed entities and data.sql can be used to populate it. While we do not recommend using multiple data source initialization technologies, if you want script-based DataSource initialization to be able to build upon the schema creation performed by Hibernate, set spring.jpa.defer-datasource-initialization to true. This will defer data source initialization until after any EntityManagerFactory beans have been created and initialized. schema.sql can then be used to make additions to any schema creation performed by Hibernate and data.sql can be used to populate it.

If you are using a Higher-level Database Migration Tool, like Flyway or Liquibase, you should use them alone to create and initialize the schema. Using the basic schema.sql and data.sql scripts alongside Flyway or Liquibase is not recommended and support will be removed in a future release.

https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto.data-initialization