Should I use One-to-Many and Many-to-One or leave them out for flexibility in SpringBoot JPA app ?

[tangara goh]

Hi experts,

I refer to the project below:

https://projects.spring.io/spring-petclinic/#quick-start

And here's my database schema which I am abit uncertain if it is correct :

Create table pets(
petId INTEGER PRIMARY KEY,
NAME VARCHAR(30) NOT NULL,
PHOTOURL VARCHAR(50) NOT NULL,
UserId INTEGER NOT NULL,
STATUS VARCHAR(30) NOT NULL,
TAGS VARCHAR(30) NOT NULL,
PRIMARY KEY (petId),
FOREIGN KEY (UserId) REFERENCES users(UserId));

Create table orders(
Id INTEGER PRIMARY KEY,
orderNumber INTEGER NOT NULL,
petId INTEGER NOT NULL,
quantity INTEGER NOT NULL,
ShipDate DATE NOT NULL,
STATUS VARCHAR(30) NOT NULL,
PRIMARY KEY(Id),
FOREIGN KEY(petId) REFERENCES pets(petId));

Create table users(
userId INTEGER PRIMARY KEY,
username VARCHAR(30) NOT NULL,
firstName VARCHAR(30) NOT NULL,
lastName VARCHAR(30) NOT NULL,
Email VARCHAR(30) NOT NULL,
Password VARCHAR(30) NOT NULL,
Phone VARCHAR(30) NOT NULL,
UserStatus VARCHAR(1) NOT NULL,
PRIMARY KEY(userId));

My question is
1) Is the above schema correct? Should I leave out reference foreign key in SpringBoot JPA web app?
2) do I need to use One-to-Many and Many-to-One to annotate the entities if the case applies? cos we can always us Join Column at the query in the Repository or Service layer for greater flexibity and perhaps 'optimization' ?
3) if the variables/attributes/fields and the names in my entity class are the same, I do not have to put @column right ?

Thank you for your help.