Reset Embedded H2 database periodically

问题

I'm setting up a new version of my application in a demo server and would love to find a way of resetting the database daily. I guess I can always have a cron job executing drop and create queries but I'm looking for a cleaner approach. I tried using a special persistence unit with drop-create approach but it doesn't work as the system connects and disconnects from the server frequently (on demand).

Is there a better approach?

回答1:

H2 supports a special SQL statement to drop all objects:

DROP ALL OBJECTS [DELETE FILES]

If you don't want to drop all tables, you might want to use truncate table:

TRUNCATE TABLE

回答2:

As this response is the first Google result for "reset H2 database", I post my solution below :

After each JUnit @tests :

Disable integrity constraint
List all tables in the (default) PUBLIC schema
Truncate all tables
List all sequences in the (default) PUBLIC schema
Reset all sequences

Reenable the constraints.

@After
public void tearDown() {
    try {
        clearDatabase();
    } catch (Exception e) {
        Fail.fail(e.getMessage());
    }
}

public void clearDatabase() throws SQLException {
    Connection c = datasource.getConnection();
    Statement s = c.createStatement();

    // Disable FK
    s.execute("SET REFERENTIAL_INTEGRITY FALSE");

    // Find all tables and truncate them
    Set<String> tables = new HashSet<String>();
    ResultSet rs = s.executeQuery("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES  where TABLE_SCHEMA='PUBLIC'");
    while (rs.next()) {
        tables.add(rs.getString(1));
    }
    rs.close();
    for (String table : tables) {
        s.executeUpdate("TRUNCATE TABLE " + table);
    }

    // Idem for sequences
    Set<String> sequences = new HashSet<String>();
    rs = s.executeQuery("SELECT SEQUENCE_NAME FROM INFORMATION_SCHEMA.SEQUENCES WHERE SEQUENCE_SCHEMA='PUBLIC'");
    while (rs.next()) {
        sequences.add(rs.getString(1));
    }
    rs.close();
    for (String seq : sequences) {
        s.executeUpdate("ALTER SEQUENCE " + seq + " RESTART WITH 1");
    }

    // Enable FK
    s.execute("SET REFERENTIAL_INTEGRITY TRUE");
    s.close();
    c.close();
}

The other solution would be to recreatethe database at the begining of each tests. But that might be too long in case of big DB.

回答3:

The command: SHUTDOWN
You can execute it using RunScript.execute(jdbc_url, user, password, "classpath:shutdown.sql", "UTF8", false);
I do run it every time when the Suite of tests is finished using @AfterClass

回答4:

Thre is special syntax in Spring for database manipulation within unit tests

@Sql(scripts = "classpath:drop_all.sql", executionPhase = Sql.ExecutionPhase.AFTER_TEST_METHOD)
@Sql(scripts = {"classpath:create.sql", "classpath:init.sql"}, executionPhase = Sql.ExecutionPhase.BEFORE_TEST_METHOD)
public class UnitTest {}

In this example we execute drop_all.sql script (where we dropp all required tables) after every test method. In this example we execute create.sql script (where we create all required tables) and init.sql script (where we init all required tables before each test method.

回答5:

If you are using spring boot see this stackoverflow question

Setup your data source. I don't have any special close on exit.

datasource: driverClassName: org.h2.Driver url: "jdbc:h2:mem:psptrx"
Spring boot @DirtiesContext annotation

@DirtiesContext(classMode = DirtiesContext.ClassMode.BEFORE_EACH_TEST_METHOD)
Use @Before to initialise on each test case.

The @DirtiesContext will cause the h2 context to be dropped between each test.

回答6:

you can write in the application.properties the following code to reset your tables which are loaded by JPA:

spring.jpa.hibernate.ddl-auto=create

来源：https://stackoverflow.com/questions/8523423/reset-embedded-h2-database-periodically

标签

reset