当我尝试脱机连接 Oracle 时，无法对脱机数据库执行命令

Question

我正在使用以下代码：

private static String file="create-table.yml";
public static void main(String[] args) throws Exception {
Database database =createOfflineDatabase("offline:oracle");
Liquibase liquibase = new Liquibase(file, new ClassLoaderResourceAccessor(), database);
liquibase.update("test");
liquibase.dropAll();
}
private static Database createOfflineDatabase(String url) throws Exception {
DatabaseConnection databaseConnection = new OfflineConnection(url, new ClassLoaderResourceAccessor());
return DatabaseFactory.getInstance().openDatabase(url, null, null, null, null);
}

获取此异常：

Exception in thread "main" liquibase.exception.MigrationFailedException: Migration failed for change set create-table.yml::create-table.yml::vishwakarma:
Reason: liquibase.exception.DatabaseException: Cannot execute commands against an offline database
at liquibase.changelog.ChangeSet.execute(ChangeSet.java:619)
at liquibase.changelog.visitor.UpdateVisitor.visit(UpdateVisitor.java:51)
at liquibase.changelog.ChangeLogIterator.run(ChangeLogIterator.java:79)
at liquibase.Liquibase.update(Liquibase.java:214)
at liquibase.Liquibase.update(Liquibase.java:192)
at liquibase.Liquibase.update(Liquibase.java:188)
at liquibase.Liquibase.update(Liquibase.java:181)
at com.test.liquibase.LiquibaseTest.main(LiquibaseTest.java:27)

我做错了什么或错过了什么吗？请帮忙。

提前致谢

Answer 1

您正在使用的Liquibase类，并且在大多数示例代码中似乎没有"updateSQL"。可以通过编程方式调用 main 方法，传入必要的--url参数以使其完成工作。例如：

liquibase.integration.commandline.Main.main(new String[]{"--changeLogFile=src/test/resources/db.changelog.xml"
,"--outputFile=target/updateSql.txt"
,"--url=offline:unknown?outputLiquibaseSql=true"
, "updateSQL"});

将生成：

-- *********************************************************************
-- Update Database Script
-- *********************************************************************
-- Change Log: src/test/resources/db.changelog.xml
-- Ran at: 12/04/20 11:51
-- Against: null@offline:unknown?outputLiquibaseSql=true
-- Liquibase version: 3.8.9
-- *********************************************************************
CREATE TABLE DATABASECHANGELOG (ID VARCHAR(255) NOT NULL, AUTHOR VARCHAR(255) NOT NULL, FILENAME VARCHAR(255) NOT NULL, DATEEXECUTED datetime NOT NULL, ORDEREXECUTED INT NOT NULL, EXECTYPE VARCHAR(10) NOT NULL, MD5SUM VARCHAR(35), DESCRIPTION VARCHAR(255), COMMENTS VARCHAR(255), TAG VARCHAR(255), LIQUIBASE VARCHAR(20), CONTEXTS VARCHAR(255), LABELS VARCHAR(255), DEPLOYMENT_ID VARCHAR(10));
-- Changeset src/test/resources/db.changelog.xml::createTable-example::liquibase-docs
CREATE TABLE public.person (address VARCHAR(255));
INSERT INTO DATABASECHANGELOG (ID, AUTHOR, FILENAME, DATEEXECUTED, ORDEREXECUTED, MD5SUM, DESCRIPTION, COMMENTS, EXECTYPE, CONTEXTS, LABELS, LIQUIBASE, DEPLOYMENT_ID) VALUES ('createTable-example', 'liquibase-docs', 'src/test/resources/db.changelog.xml', CURRENT_TIMESTAMP, 1, '8:49e8eb557129b33d282c4ad2fdc5d4d9', 'createTable tableName=person', '', 'EXECUTED', NULL, NULL, '3.8.9', '6688703163');

并且还输出一个databasechangelog.csv，用于跟踪后续运行的数据库更改日志的状态。

如果您编辑代码以加载"db.changelog2.xml"，其中包含具有不同ID的新内容，并告诉它将sql写出到仅设置第二个更改的新文件中。这是因为databasechangelog.csv将用于了解以前运行的内容。然后，CSV 将在下次更新：

"ID","AUTHOR","FILENAME","DATEEXECUTED","ORDEREXECUTED","EXECTYPE","MD5SUM","DESCRIPTION","COMMENTS","TAG","LIQUIBASE","CONTEXTS","LABELS","DEPLOYMENT_ID"
"createTable-example","liquibase-docs","src/test/resources/db.changelog.xml","2020-04-12T12:10:16.989","2","EXECUTED","8:49e8eb557129b33d282c4ad2fdc5d4d9","createTable tableName=person","","","3.8.9","()","","6689816939"
"createTable-example2","liquibase-docs","src/test/resources/db.changelog2.xml","2020-04-12T12:26:56.664","4","EXECUTED","8:3740614394b969eeb1edcc9fd0187bdb","createTable tableName=person2",,"","3.8.9","()","","6690816645"

警告：似乎如果你直接调用main方法，它将在内部调用System.exit()所以如果你真的想在工具中运行updateSQL，你需要查看该主类中的代码，以确定如何在没有JVM被System.exit()终止的情况下做到这一点。

Answer 2

离线数据库是Liquibase想出的东西，允许您生成SQL来更新liquibase用户无法直接更新的数据库 - 它们无法更新。有关脱机数据库的更多详细信息，请参阅此文档。