Hibernate creating new columns on existing table running with springboot - mysql

Question

On running my springboot application hibernate is creating new columns.
Below is my entity class
#Entity
#Table(name="contst_games")
public class ContestGames {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="id")
private int id;
#Column(name="cntstName")
private String contestName;
#Column(name="cntstType")
private String contestType;
#Column(name="phne")
private int phoneNumbr;
// getters and setters
#Override
public String toString() {
return "ContestGames [id=" + id + ", contestName=" + contestName + ", contestType=" + contestType + "]";
}
}
Below is the setup of properties
# ==========================================================================
# = JPA / HIBERNATE
# ==========================================================================
spring.jpa.database-platform = org.hibernate.dialect.MySQL5Dialect
spring.jpa.show-sql = true
#60 sec
spring.datasource.hikari.connection-timeout=60000
# max 5
spring.datasource.hikari.maximum-pool-size=5
spring.jpa.hibernate.ddl-auto=update
#============================================================================
Below is the newly created table
'id', 'int(11)', 'NO', 'PRI', NULL, 'auto_increment'
'cntstName', 'varchar(255)', 'YES', '', NULL, ''
'cntstType', 'varchar(255)', 'YES', '', NULL, ''
'phne', 'int(11)', 'YES', '', NULL, ''
'cntst_name', 'varchar(255)', 'YES', '', NULL, ''
'cntst_type', 'varchar(255)', 'YES', '', NULL, ''
Below is the alter query that is being run on running the application.
2019-11-28 13:09:23.092 INFO 10615 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [name: default]
2019-11-28 13:09:23.158 INFO 10615 --- [ main] org.hibernate.Version : HHH000412: Hibernate Core {5.4.8.Final}
2019-11-28 13:09:23.344 INFO 10615 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
2019-11-28 13:09:23.446 INFO 10615 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2019-11-28 13:09:23.450 WARN 10615 --- [ main] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
2019-11-28 13:09:23.669 INFO 10615 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2019-11-28 13:09:23.688 INFO 10615 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect
Hibernate: alter table contst_games add column cntst_name varchar(255)
Hibernate: alter table contst_games add column cntst_type varchar(255)
2019-11-28 13:09:24.867 INFO 10615 --- [ main] o.h.e.t.j.p.i.JtaPlatformInitiator : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2019-11-28 13:09:24.891 INFO 10615 --- [ main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2019-11-28 13:09:25.482 WARN 10615 --- [ main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
Two new columns cntst_name and cntst_type are being created at runtime. Ideally no new column should be added since the table already exists and spring.jpa.hibernate.ddl-auto=update. Also to be noted no new column for phone number is being created.

Answer 1

That's because of Hibernate&Spring Boot Naming Strategies.
(more info: https://www.jpa-buddy.com/blog/hibernate-naming-strategies-jpa-specification-vs-springboot-opinionation)
So,
the right way is to name your columns strictly in a snake_case, NOT camelCase or PascalCase.