Spring In Action chapter 3 - issues after migration to JPA

[MuhammadFaiq123]

I am creating this thread to share some of the problems that I faced at the end of the chapter 3 after migration to JPA. I believe the steps provided in the book are not enough and I had to change some of the things to make the things work.

Feel free to add your experience in this.

[MuhammadFaiq123]

Issue:
org.h2.jdbc.JdbcSQLSyntaxErrorException: Sequence "HIBERNATE_SEQUENCE" not found; SQL statement:
call next value for hibernate_sequence [90036-214]

Solution:

The error message suggests that the sequence "HIBERNATE_SEQUENCE" is not found in the H2 database. This sequence is commonly used by Hibernate to generate unique IDs for entities.

So, please add below line in the "schema.sql" file:
CREATE SEQUENCE HIBERNATE_SEQUENCE START WITH 1 INCREMENT BY 1;

[MuhammadFaiq123]

Issue:
insert into Taco_Ingredient (Taco_id, ingredients_id) values (?, ?) [42122-214]
2023-05-05 00:58:39.753 ERROR 35536 --- [nio-8080-exec-6] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not prepare statement; SQL [insert into Taco_Ingredient (Taco_id, ingredients_id) values (?, ?)]; nested exception is org.hibernate.exception.SQLGrammarException: could not prepare statement] with root cause

org.h2.jdbc.JdbcSQLSyntaxErrorException: Column "TACO_ID" not found; SQL statement:
insert into Taco_Ingredient (Taco_id, ingredients_id) values (?, ?) [42122-214]

Solution:

Change the schema and add Taco_id and ingredients_id in respective tables because when you added @manytomany annotation in the beans of Taco and Ingredient then the JPA would by default first find the table Taco_Ingredient by combining these two and then find its primary keys by following [fieldName in beans class on which ManytoMany annotaiton is added] + "_" + "id"