I have an application which was running on H2 database and Hibernate is the ORM tool. Currently, I am changing this application to use mysql database instead of H2 database and while doing this I came to this issue when saving flagjp entity.
Here is the FlagJP entity that caused this issue.
Code:
@Entity
public class FlagJP extends BaseModelJP {
@Id
@GeneratedValue(generator = "IdOrGenerated")
@GenericGenerator(name = "IdOrGenerated", strategy = "com.jp.menu.api.model.JPSequenceGenerator")
private Long flagId;
private String flagKey;
@OneToMany(mappedBy="flag", cascade = CascadeType.ALL)
private List<FlagLangJP> flagLangs = new ArrayList<>();
@ManyToOne
private FlagCategoryJP flagCategory;
Here are the related entities for the FlagJP
Second entity
Code:
@Entity
public class FlagLangJP extends BaseModelJP {
@Id
@GeneratedValue(generator = "IdOrGenerated")
@GenericGenerator(name = "IdOrGenerated", strategy = "com.jp.menu.api.model.JPSequenceGenerator")
private Long id;
private String languageCode;
private String flagName;
private String flagDescription;
@ManyToOne
private FlagJP flag;
Third Entity
Code:
@Entity
public class FlagCategoryJP extends BaseModelJP {
@Id
@GeneratedValue(generator = "IdOrGenerated")
@GenericGenerator(name = "IdOrGenerated", strategy = "com.jp.menu.api.model.JPSequenceGenerator")
private Long flagCategoryId;
private String flagCategoryName;
@OneToMany(mappedBy = "flagCategory")
private List<FlagJP> flags;
While looking into this issue, I was able to figure out that this is cased by FlagJP table schema not having auto increment set in the database when hibernate generated the DDL.
here is the DDL of FlagJP
If I try to manually set the auto increment by executing a sql query, then mysql throw this error.
Code:
Operation failed: There was an error while applying the SQL script to the database.
ERROR 1833: Cannot change column 'flagId': used in a foreign key constraint 'FK_sk95esyf1n0gt1qqmlmdmq0uw' of table 'butterfly_emenu.flaglangbpa'
SQL Statement:
my question is , this problem does not happen when using H2 database. how to solve this issue using hibernate when the database is mysql.
Thanks in advance for any advice
Update:
Here is the code for sequence generator I am using
Code:
public class JPSequenceGenerator extends IdentityGenerator {
private static final Logger logger = LoggerFactory.getLogger(JPSequenceGenerator.class);
@Override
public Serializable generate(SessionImplementor session, Object object) throws HibernateException {
Serializable id = session.getEntityPersister(null, object).getClassMetadata().getIdentifier(object, session);
if (id == null) {
id = super.generate(session, object);
}
return id;
}
}
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