title: Spring boot H2 db mode oracle
body: <p>Hi I have a spring boot app (2.3.1.RELEASE, ojdbc8) and basically it is connected to an oracle database.</p>
  <p>The spring boot app starts find when it is connected to the oracle db.However fails to start when
  the integration test is connected to a H2 embedded db and some of my queries are failing with the following error message:</p>
  <pre><code>Caused by: java.lang.NullPointerException: null
      at org.hibernate.hql.internal.NameGenerator.generateColumnNames(NameGenerator.java:27)
      at org.hibernate.hql.internal.ast.util.SessionFactoryHelper.generateColumnNames(SessionFactoryHelper.java:434)
  </code></pre>
  <p>I manage to make it work by adding adding the following line of code in my application-test.yml file:</p>
  <pre><code>spring:
    jpa:
      database-platform: org.hibernate.dialect.Oracle10gDialect
  </code></pre>
  <p>Please fine below application-test.yml config:</p>
  <pre><code>spring.datasource:
    url: jdbc:h2:mem:db;Mode=Oracle;DB_CLOSE_DELAY=-1
    username: sa
    password: sa
    driverClassName: org.h2.Driver
  # added empty context path to override application.yml context path
  server:
    servlet:
      contextPath:
  spring:
    jpa:
      database-platform: org.hibernate.dialect.Oracle10gDialect
  </code></pre>
  <p>The application starts well and integration completed successfully however the following exception can be shown in the log:</p>
  <pre><code>org.h2.jdbc.JdbcSQLSyntaxErrorException: Table &quot;ALL_SEQUENCES&quot; not found; SQL statement:
  select * from all_sequences [42102-200]
      at org.h2.message.DbException.getJdbcSQLException(DbException.java:453) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.message.DbException.getJdbcSQLException(DbException.java:429) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.message.DbException.get(DbException.java:205) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.message.DbException.get(DbException.java:181) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.command.Parser.readTableOrView(Parser.java:7628) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.command.Parser.readTableFilter(Parser.java:1970) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.command.Parser.parseSelectFromPart(Parser.java:2827) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.command.Parser.parseSelect(Parser.java:2959) ~[h2-1.4.200.jar:1.4.200]
      
      
      ....
      
      org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL &quot;drop table dash_processed cascade constraints&quot; via JDBC Statement
      at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlString(SchemaDropperImpl.java:375) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlStrings(SchemaDropperImpl.java:359) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.internal.SchemaDropperImpl.dropFromMetadata(SchemaDropperImpl.java:241) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.internal.SchemaDropperImpl.performDrop(SchemaDropperImpl.java:154) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:126) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:112) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:145) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73) ~[hibernate-core-5.4.17.Final.jar:5.4.17.Final]
      
      ...
      
      drop table dash_processed cascade constraints [42102-200]
      at org.h2.message.DbException.getJdbcSQLException(DbException.java:453) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.message.DbException.getJdbcSQLException(DbException.java:429) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.message.DbException.get(DbException.java:205) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.message.DbException.get(DbException.java:181) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.command.ddl.DropTable.prepareDrop(DropTable.java:65) ~[h2-1.4.200.jar:1.4.200]
      at org.h2.command.ddl.DropTable.update(DropTable.java:124) ~[h2-1.4.200.jar:1.4.200]
  </code></pre>
  <p>Any idea how i can stop those errors?</p>
  <p>Thanks in advance</p>