java - 从.sql加载模式以在Spring Boot中创建orm映射

Question

有没有办法在启动服务器时从 .sql 或 json 或文本文件加载数据库架构，以在 spring-boot 中使用 JPA/Hibernate 创建 ORM 映射到数据库。

Answer 1

Spring Boot 使您可以使用数据库迁移工具，例如 Liquibase和 Flyway ，您可以在Spring's official documentation上阅读更多相关信息。 .

编辑:来自文档

85.5 Use a Higher-level Database Migration Tool

Spring Boot supports two higher-level migration tools: Flyway and Liquibase.

85.5.1 Execute Flyway Database Migrations on Startup

To automatically run Flyway database migrations on startup, add the org.flywaydb:flyway-core to your classpath.

The migrations are scripts in the form V__.sql (with an underscore-separated version, such as ‘1’ or ‘2_1’). By default, they are in a folder called classpath:db/migration, but you can modify that location by setting spring.flyway.locations. This is a comma-separated list of one or more classpath: or filesystem: locations. For example, the following configuration would search for scripts in both the default classpath location and the /opt/migration directory:

spring.flyway.locations=classpath:db/migration,filesystem:/opt/migration You can also add a special {vendor} placeholder to use vendor-specific scripts. Assume the following:

spring.flyway.locations=classpath:db/migration/{vendor} Rather than using db/migration, the preceding configuration sets the folder to use according to the type of the database (such as db/migration/mysql for MySQL). The list of supported databases is available in DatabaseDriver.

FlywayProperties provides most of Flyway’s settings and a small set of additional properties that can be used to disable the migrations or switch off the location checking. If you need more control over the configuration, consider registering a FlywayConfigurationCustomizer bean.

Spring Boot calls Flyway.migrate() to perform the database migration. If you would like more control, provide a @Bean that implements FlywayMigrationStrategy.

Flyway supports SQL and Java callbacks. To use SQL-based callbacks, place the callback scripts in the classpath:db/migration folder. To use Java-based callbacks, create one or more beans that implement Callback. Any such beans are automatically registered with Flyway. They can be ordered by using @Order or by implementing Ordered. Beans that implement the deprecated FlywayCallback interface can also be detected, however they cannot be used alongside Callback beans.

By default, Flyway autowires the (@Primary) DataSource in your context and uses that for migrations. If you like to use a different DataSource, you can create one and mark its @Bean as @FlywayDataSource. If you do so and want two data sources, remember to create another one and mark it as @Primary. Alternatively, you can use Flyway’s native DataSource by setting spring.flyway.[url,user,password] in external properties. Setting either spring.flyway.url or spring.flyway.user is sufficient to cause Flyway to use its own DataSource. If any of the three properties has not be set, the value of its equivalent spring.datasource property will be used.

There is a Flyway sample so that you can see how to set things up.

You can also use Flyway to provide data for specific scenarios. For example, you can place test-specific migrations in src/test/resources and they are run only when your application starts for testing. Also, you can use profile-specific configuration to customize spring.flyway.locations so that certain migrations run only when a particular profile is active. For example, in application-dev.properties, you might specify the following setting:

spring.flyway.locations=classpath:/db/migration,classpath:/dev/db/migration With that setup, migrations in dev/db/migration run only when the dev profile is active.

85.5.2 Execute Liquibase Database Migrations on Startup

To automatically run Liquibase database migrations on startup, add the org.liquibase:liquibase-core to your classpath.

By default, the master change log is read from db/changelog/db.changelog-master.yaml, but you can change the location by setting spring.liquibase.change-log. In addition to YAML, Liquibase also supports JSON, XML, and SQL change log formats.

By default, Liquibase autowires the (@Primary) DataSource in your context and uses that for migrations. If you need to use a different DataSource, you can create one and mark its @Bean as @LiquibaseDataSource. If you do so and you want two data sources, remember to create another one and mark it as @Primary. Alternatively, you can use Liquibase’s native DataSource by setting spring.liquibase.[url,user,password] in external properties. Setting either spring.liquibase.url or spring.liquibase.user is sufficient to cause Liquibase to use its own DataSource. If any of the three properties has not be set, the value of its equivalent spring.datasource property will be used.

See LiquibaseProperties for details about available settings such as contexts, the default schema, and others.

There is a Liquibase sample so that you can see how to set things up.

Spring 还支持自己的数据库初始化， official docs are here .

Spring Boot can automatically create the schema (DDL scripts) of your DataSource and initialize it (DML scripts). It loads SQL from the standard root classpath locations: schema.sql and data.sql, respectively.