How to trigger a cronjob during initialization - sap-commerce-cloud

Question

I want to trigger a cronjob which will delete some index and recreate it on initialization as a one time activity i.e cronjob should run only once.
How to achieve it?

Answer 1

Firstly you can create index with items.xml like below. This OOTB future auto create index on initialization or update.
<itemtype code="myType" autocreate="true" generate="true">
<attributes>
...
</attributes>
<indexes>
<index name="myIndex" unique="true">
<key attribute="myField1" />
<key attribute="myField2" />
</index>
</indexes>
</itemtype>
You can cover this scenario but you will lose database independency. You can connect to db directly with jdbc using spring beans and drop index with DDL command. You can check below groovy script for this.
import java.util.List;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
def config = spring.getBean("configurationService").getConfiguration();
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName(config.getString("db.driver"));
dataSource.setUrl(config.getString("db.url"));
dataSource.setUsername(config.getString("db.username"));
dataSource.setPassword(config.getString("db.password"));
JdbcTemplate jdbc = new JdbcTemplate(dataSource)
jdbc.execute("ALTER TABLE MYTABLE ALTER (P_MYFIELD BIGINT)");
For creating index at initialization step you need to extend AbstractSystemSetup class. If you can add your index with items.xml, you will not need to extend this class.