使用Flyway做数据库变更版本控制

我会带着你远行 2022-04-14 03:50 511阅读 0赞

### 文章目录 ###

*  使用Flyway做数据库变更版本控制
 *   *  前言
     *  Flyway介绍
     *  使用Flyway对Spring Boot项目做数据库变更版本控制
     *  后记
     *  参考文档
     *  附录
     *   *  Flyway properties

# 使用Flyway做数据库变更版本控制 #

## 前言 ##

在DevOps部署流水线中，需要对数据库变更做版本控制，要求能够做到：

*  对数据库变更做版本控制
 *  执行数据库增量变更，包括执行DDL和DML语句
 *  防止重复执行
 *  一次编写SQL，多环境运行

## Flyway介绍 ##

[Flyway][] 是一个简单而强大的数据库变更版本控制工具。

Flyway支持通过`.sql`文件来对数据库变更脚本做版本控制，`.sql`文件的命名规范为

V{version}__{description}.sql

*  大写的V表示该脚本为[Flyway Versioned Migration Script][]
 *  version为递增的数据库变更脚本版本号
 *  `__`两个下划线用来分隔version和description
 *  description为脚本描述

Flyway通过在数据库中创建`flyway_schema_history`表来记录数据库变更历史，并防止重复执行脚本和检查之前检查过的脚本是否被篡改。

![flyway\_schema\_hisotry][flyway_schema_hisotry]

Flyway支持与Maven和Gradle集成，使得可以不用安装其它工具，就可以在项目中直接使用Flyway来做数据库变更版本控制。

## 使用Flyway对Spring Boot项目做数据库变更版本控制 ##

下面介绍在Spring Boot项目（用Maven管理依赖）中如何通过Flyway来做数据库变更版本控制。

在`pom.xml`文件中添加Flyway的依赖：

<dependency>
    	<groupId>org.flywaydb</groupId>
    	<artifactId>flyway-core</artifactId>
    </dependency>

在Spring Boot的配置文件（比如application.properties）中配置Flyway的属性：

# 默认flyway.enabled=true
    flyway.enabled=true
    # 默认flyway.locations=classpath:db/migration
    flyway.locations=classpath:db/migration

Flyway默认使用和Spring Boot相同的数据库连接。

> 完整的Flyway的属性参见文末的Flyway properties

在`src/main/resources`目录下创建`db/migration`目录，并将`.sql`文件放在该目录下。

> `.sql`文件需要符合上面提到的Flyway命名规范。

在Spring Boot程序运行时，会通过Flyway自动在数据库中创建`flyway_schema_history`表来记录数据库变更历史，并自动执行数据库变更脚本。

完整的示例代码参见[flyway-demo][]

> 结合Spring的profile注入功能，可以控制某些`.sql`文件只在特定环境的数据库中执行。

## 后记 ##

Liquibase也可以实现和Flyway一样的数据库变更版本控制功能。关于这两者的区别，请参考下面这篇文章：

*  [https://stackshare.io/stackups/flyway-vs-liquibase][https_stackshare.io_stackups_flyway-vs-liquibase]

## 参考文档 ##

*  [https://javadeveloperzone.com/spring-boot/spring-boot-flyway-example/][https_javadeveloperzone.com_spring-boot_spring-boot-flyway-example]
 *  [https://blog.csdn.net/xiang\_\_liu/article/details/82780201][https_blog.csdn.net_xiang_liu_article_details_82780201]

## 附录 ##

### Flyway properties ###

# The description to tag an existing schema with when executing baseline.
    flyway.baseline-description=
    # Version to start migration.
    flyway.baseline-version=1
    # Whether to execute migration against a non-empty schema with no metadata table
    flyway.baseline-on-migrate=false
    # Check that migration scripts location exists.
    flyway.check-location=false
    # will clean all objects. Warning! Do NOT enable in production!
    flyway.clean-on-validation-error=false
    # Enable flyway.
    flyway.enabled=true
    # The encoding of migrations.
    flyway.encoding=UTF-8
    # Ignore future migrations when reading the metadata table.
    flyway.ignore-failed-future-migration=true
    # SQL statements to execute to initialize a connection immediately after obtaining it.
    flyway.init-sqls= 
    # locations of migrations scripts.
    flyway.locations=classpath:db/migration
    # Allows migrations to be run "out of order".
    flyway.out-of-order=false
    # The prefix of every placeholder.
    flyway.placeholder-prefix=
    # Whether placeholders should be replaced.
    flyway.placeholder-replacement=true
    # The suffix of every placeholder.
    flyway.placeholder-suffix=}
    # Placeholders to replace in Sql migrations.
    flyway.placeholders.*=
    # Default schema of the connection and updating
    flyway.schemas=
    # The file name prefix for Sql migrations
    flyway.sql-migration-prefix=V
    # The file name separator for Sql migrations
    flyway.sql-migration-separator=__
    # The file name suffix for Sql migrations
    flyway.sql-migration-suffix=.sql
    # The name of Flyway's metadata table.
    flyway.table=schema_version
    # JDBC url of the database to migrate. If not set, the primary configured data source is used.
    flyway.url=
    # Login user of the database to migrate. If not set, use spring.datasource.username value.
    flyway.user=
    # JDBC password if you want Flyway to create its own DataSource.
    flyway.password=
    # Validate sql migration CRC32 checksum in classpath
    flyway.validate-on-migrate=true.

[Flyway]: https://flywaydb.org/
[Flyway Versioned Migration Script]: https://flywaydb.org/documentation/migrations#versioned-migrations
[flyway_schema_hisotry]: /images/20220414/bce0392af93c41c190cf5624e5d77ab9.png
[flyway-demo]: https://github.com/cookcodeblog/flyway-demo
[https_stackshare.io_stackups_flyway-vs-liquibase]: https://stackshare.io/stackups/flyway-vs-liquibase
[https_javadeveloperzone.com_spring-boot_spring-boot-flyway-example]: https://javadeveloperzone.com/spring-boot/spring-boot-flyway-example/
[https_blog.csdn.net_xiang_liu_article_details_82780201]: https://blog.csdn.net/xiang__liu/article/details/82780201