[Data] gradle+mysql+jpa

[1] Create the application.properties File

spring.jpa.hibernate.ddl-auto=update

#none: No change is made to the database structure.  (good choice)
#update: Hibernate changes the database according to the given entity structures.
#create: Creates the database every time but does not drop it on close.
#create-drop: Creates the database and drops it when SessionFactory closes.

 

* Mysql default : none

* H2 and etc...  : create-drop

<!> You must begin with either create or update, because you do not yet have the database structure.

After the first run, you can switch it to update or none

 

spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/db_example
spring.datasource.username=springuser
spring.datasource.password=ThePassword

 

[2] Create the @Entity Model

Hibernate automatically translates the entity into a table.

[3] Create the Repository

Spring automatically implements this repository interface in a bean that has the same name

ex) name change crudRepository -> userRepository

[4] Create a Controller