Software Development & Operating Systems

Notes on Software Development & Operating Systems


Options for spring.jpa.hibernate.ddl-auto

validate: validate the schema, makes no changes to the database. update: update the schema. create: creates the schema, destroying previous data. create-drop: drop the schema when the SessionFactory is closed explicitly, typically when the application is stopped.

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Configure SpringBoot with H2 Database

Prerequisite: Go to and create a new SpringBoot project with Web, H2, and DevTools for dependencies. Import new project into STS (Spring Tools Suite). Additions to Open /src/main/resources/ and add the following lines: # H2 spring.h2.console.enabled=true spring.h2.console.path=/h2 # Datasource spring.datasource.url=jdbc:h2:file:~/test spring.datasource.username=sa spring.datasource.password= spring.datasource.driver-class-name=org.h2.Driver spring.jpa.database-platform=org.hibernate.dialect.H2Dialect spring.jpa.generate-ddl=true spring.jpa.hibernate.ddl-auto=validate NOTE: If you want your database [...]

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JPA: How to use a base class for your entities

In order for to extend a base class from you entities, you must use the annotation @MappedSuperclass on the base class: @MappedSuperclass public abstract class AbstractBaseEntity Then in your entity class extend the class as you usually would: @Entity public class MyConcreteEntity extends AbstractBaseEntity

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How to resolve LazyInitializationException with SpringMVC using JPA with Hibernate

Follow the below steps if you see the org.hibernate.LazyInitializationException being thrown while trying to render your page. Add a filter to your web.xml file: <filter> <filter-name>SpringOpenEntityManagerInViewFilter</filter-name> <filter-class></filter-class> </filter> <filter-mapping> <filter-name>SpringOpenEntityManagerInViewFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>

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