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Java Springboot JPA joining multiple tables

I'm new to Java Springboot and I want to join multiple tables.
I have this MySQL schema :
CREATE TABLE `users`
(
`id` int NOT NULL AUTO_INCREMENT,
`email` varchar(128) NOT NULL,
`nickname` varchar(128) NOT NULL,
`password` varchar(256) NOT NULL,CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
UNIQUE KEY `email` (`email`),
UNIQUE KEY `nickname` (`nickname`)
);
CREATE TABLE `organizations` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(128) NOT NULL,
PRIMARY KEY (`id`)
);
CREATE TABLE `org_abilities`
(
`id` int NOT NULL AUTO_INCREMENT,
`key` varchar(128) NOT NULL,
`description` varchar(128) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `idx_key` (`key`) USING BTREE
);
CREATE TABLE `org_permissions`
(
`id` int NOT NULL AUTO_INCREMENT,
`id_user` int NOT NULL,
`id_organization` int NOT NULL,
`id_ability` int NOT NULL,
PRIMARY KEY (`id`),
KEY `id_organization` (`id_organization`),
KEY `id_user` (`id_user`),
KEY `users_permissions_ibfk_2` (`id_ability`),
CONSTRAINT `org_permissions_ibfk_0` FOREIGN KEY (`id_organization`) REFERENCES `organizations` (`id`),
CONSTRAINT `org_permissions_ibfk_1` FOREIGN KEY (`id_user`) REFERENCES `users` (`id`),
CONSTRAINT `org_permissions_ibfk_2` FOREIGN KEY (`id_ability`) REFERENCES `org_abilities` (`id`)
);
Where my table org_permissions represent all abilities that a user has within an organization.
I have created the corresponding Java classes. I have a JPA to fetch the datas from the DB to the classes.
I want in my Organization class to have a field Map<long, List<Pair<long, String>>> managers which map an id_user to a list of tuple of abilities where the tuple is (id_ability, org_ability.key).
Finally I use DTO to send my response, and I want my response to look like that :
{
id : _id_organization,
name : "organisation name",
managers : {
id_user: [(id_ability, key), (id_ability, key)],
id_user:[(id_ability, key), (id_ability, key)]
}
}
For example:
SELECT op.*, oa.* FROM org_permissions as op
JOIN org_abilities oa on oa.id = op.id_ability
JOIN organizations o on o.id = op.id_organization
JOIN users u on u.id = op.id_user;
Here, user with id 1 is member of organization 1 and 2. for organization 1 user 1 has the CREATE_EVENTS and DELETE_EVENTS abilities and for organization 2 he only have the DELETE_EVENTS ability.
When getting all the organization I want this result :
[{
id : 1,
name : "Org1",
managers : {
1: [(1, "CREATE_EVENT"), (2,"CREATE_EVENT")]
}
},
{
id : 2,
name : "Org2",
managers : {
1: [(2,"CREATE_EVENT")]
}
}]
Thanks for your help, I'm a bit lost with the High level of springboot and JPA
P.S.: I tried to ask to chat GPT but nothing was concluent

Why a SQL SELECT statement doesn't return COUNT() result on Java Spring boot project?

this is my first question here so, please ask if you need more information. I am working on a personal project. I have a relatively complex relational database structure. I create schema.sql on my spring boot project as well as data.sql with sample data. I try to create a web application for simulated fitness centre web pages. I try to display the location name and number of visits for the user. I create a userLocation bean for keeping the result set as a list of the select query. I can test the statement on H2 database and its work. However, on my code, I cannot get the number of visits from the select statement.
Here is my userlocation bean,
#Data
#NoArgsConstructor
public class UserLocation {
private String locName;
private int numOfVisit;
}
Controller class getMapping method
#GetMapping("/secure/userLocation")
public String myLocation(Model model, Authentication authentication) {
String email = authentication.getName();
User currentUser = da.findUserAccount(email);
model.addAttribute("myLocationList", da.getUserLocationList(currentUser.getUserId()));
return "/secure/userLocation";
}
Here database access method;
public List<UserLocation> getUserLocationList(Long userId) {
MapSqlParameterSource namedParameters = new MapSqlParameterSource();
String query = "SELECT l.locName, COUNT(ul.dayOfVisit) FROM location l "
+ "INNER JOIN userLocation ul ON l.locId = ul.locId "
+ "INNER JOIN sec_user sc ON ul.userId = sc.userId "
+ "WHERE sc.userId = :userId AND ul.locId = 1"
+ "GROUP BY l.locName";
namedParameters.addValue("userId", userId);
return jdbc.query(query, namedParameters, new BeanPropertyRowMapper<UserLocation>(UserLocation.class));
}
here schema.sql
CREATE TABLE location (
locId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
locName VARCHAR(75),
locAddress VARCHAR(255),
locPhone VARCHAR(25),
locEmail VARCHAR(75)
);
CREATE TABLE sec_user (
userId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(75),
lastName VARCHAR(75),
adress VARCHAR(255),
phone VARCHAR(10),
email VARCHAR(75) NOT NULL UNIQUE,
encryptedPassword VARCHAR(128) NOT NULL,
enabled BIT NOT NULL
);
CREATE TABLE coach (
coachId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
coachName VARCHAR(75),
coachLevel BIGINT,
coachRating BIGINT,
aboutMe VARCHAR(255)
);
CREATE TABLE fitnessClass (
classId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
className VARCHAR(75),
classPrice DOUBLE
);
CREATE TABLE generalCert (
certId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
certName VARCHAR(75)
);
CREATE TABLE certCoach (
certId BIGINT NOT NULL,
coachId BIGINT NOT NULL
);
ALTER TABLE certCoach
ADD CONSTRAINT certCoach_FK1 FOREIGN KEY (certId)
REFERENCES generalCert (certId);
ALTER TABLE certCoach
ADD CONSTRAINT certCoach_FK2 FOREIGN KEY (coachId)
REFERENCES coach (coachId);
CREATE TABLE userLocation (
userLocId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
locId BIGINT NOT NULL,
userId BIGINT NOT NULL,
isHomeLoc BIT,
dayOfVisit DATE
);
ALTER TABLE userLocation
ADD CONSTRAINT userLocation_FK1 FOREIGN KEY (locId)
REFERENCES location (locId);
ALTER TABLE userLocation
ADD CONSTRAINT userLocation_FK2 FOREIGN KEY (userId)
REFERENCES sec_user (userId);
CREATE TABLE amenity (
amenityId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
amenityName VARCHAR(75),
locId BIGINT
);
ALTER TABLE amenity
ADD CONSTRAINT amenity_FK FOREIGN KEY (locId)
REFERENCES location (locId);
CREATE TABLE room (
roomId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
roomName VARCHAR(75),
locId BIGINT
);
ALTER TABLE room
ADD CONSTRAINT room_FK FOREIGN KEY (locId)
REFERENCES location (locId);
CREATE TABLE classCoach (
classId BIGINT NOT NULL,
coachId BIGINT NOT NULL
);
ALTER TABLE classCoach
ADD CONSTRAINT classCoachFK1 FOREIGN KEY (classId)
REFERENCES fitnessClass(classId);
ALTER TABLE classCoach
ADD CONSTRAINT classCoachFK2 FOREIGN KEY (coachId)
REFERENCES coach(coachId);
CREATE TABLE schedule (
ScheduleId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
ScheduleDate DATE,
ScheduleTime TIME,
RoomId BIGINT,
ClassId BIGINT NOT NULL,
LocId BIGINT NOT NULL
);
ALTER TABLE schedule
ADD CONSTRAINT scheduleFK1 FOREIGN KEY (roomId)
REFERENCES room(RoomId);
ALTER TABLE schedule
ADD CONSTRAINT scheduleFK2 FOREIGN KEY (classId)
REFERENCES fitnessClass(classId);
ALTER TABLE schedule
ADD CONSTRAINT ScheduleFK3 FOREIGN KEY (LocId)
REFERENCES location(LocId);
CREATE TABLE reservation (
ClassId BIGINT NOT NULL,
userId BIGINT NOT NULL
);
ALTER TABLE reservation
ADD CONSTRAINT reservationFK1 FOREIGN KEY (classId)
REFERENCES fitnessClass(classId);
ALTER TABLE reservation
ADD CONSTRAINT reservationFK2 FOREIGN KEY (userId)
REFERENCES sec_user(userId);
CREATE TABLE workFrom (
coachId BIGINT NOT NULL,
locId BIGINT NOT NULL
);
ALTER TABLE workFrom
ADD CONSTRAINT workFromFK1 FOREIGN KEY (coachId)
REFERENCES coach(coachId);
ALTER TABLE workFrom
ADD CONSTRAINT workFromFK2 FOREIGN KEY (locId)
REFERENCES location(locId);
CREATE TABLE review (
ReviewId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
CoachId BIGINT NOT NULL,
userId BIGINT NOT NULL,
ReviewDate DATE,
ComScore CHAR(1),
EnthScore CHAR(1),
PunctScore CHAR(1),
ReviewText VARCHAR(500)
);
ALTER TABLE review
ADD CONSTRAINT reviewFK1 FOREIGN KEY (coachId)
REFERENCES coach(coachId);
ALTER TABLE review
ADD CONSTRAINT reviewFK2 FOREIGN KEY (userId)
REFERENCES sec_user(userId);
CREATE TABLE Reference (
CoachId BIGINT NOT NULL,
userId BIGINT NOT NULL
);
ALTER TABLE Reference
ADD CONSTRAINT ReferenceFK1 FOREIGN KEY (coachId)
REFERENCES coach(coachId);
ALTER TABLE review
ADD CONSTRAINT ReferenceFK2 FOREIGN KEY (userId)
REFERENCES sec_user(userId);
CREATE TABLE ClientCoach (
coachId BIGINT NOT NULL,
userId BIGINT NOT NULL,
myCoach BIT
);
ALTER TABLE ClientCoach
ADD CONSTRAINT ClientCoachFK1 FOREIGN KEY (coachId)
REFERENCES coach(coachId);
ALTER TABLE ClientCoach
ADD CONSTRAINT ClientCoachFK2 FOREIGN KEY (userId)
REFERENCES sec_user(userId);
CREATE TABLE sec_role(
roleId BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
roleName VARCHAR(30) NOT NULL UNIQUE
);
CREATE TABLE user_role
(
id BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
userId BIGINT NOT NULL,
roleId BIGINT NOT NULL
);
ALTER TABLE user_role
ADD CONSTRAINT user_role_uk UNIQUE (userId, roleId);
ALTER TABLE user_role
ADD CONSTRAINT user_role_fk1 FOREIGN KEY (userId)
REFERENCES sec_user (userId);
ALTER TABLE user_role
ADD CONSTRAINT user_role_fk2 FOREIGN KEY (roleId)
REFERENCES sec_role (roleId);
Here the result web page
Here is EERD for the schema

Please try:
SELECT l.locName, COUNT(ul.dayOfVisit) AS numOfVisit -- ...
(to alias numOfVisit), since we are using a BeanPropertyRowMapper (which mapps by "bean properties" (i.e. "field names"): https://www.google.com/search?q=java+bean+naming+conventions).
Alternatively use an other/custom RowMapper.
And since even javadoc recommends:
... For best performance, consider using a custom RowMapper implementation.
Best:
return jdbc.query(query, namedParameters,
(ResultSet rs, int rowNum) -> { // one ResultSet per row:
// column indices start with 1(!):
return new UserLocation(rs.getString(1), rs.getInt(2));
// alternatively (name based): rs.getString("locName")...
}
);
;)
RowMapper javadoc (spring-jdbc:current)
ResultSet javadoc (jdk17)
and since RowMapper is a/meets the requirements of a functional interface, we can write it as lambda expression.

How to understand the "type" field in the result of using "explain" on Mysql?

When I used "explain" on Mysql to view some information about the execution of the statement, the value of the field type made me very confused!
Table creation statement
DROP TABLE IF EXISTS `actor`;
CREATE TABLE `actor` (
`id` int(11) NOT NULL,
`name` varchar(45) DEFAULT NULL,
`update_time` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `actor` (`id`, `name`, `update_time`) VALUES (1,'a','2017-12-2 15:27:18'), (2,'b','2017-12-22 15:27:18'), (3,'c','2017-12-22 15:27:18');
DROP TABLE IF EXISTS `film`;
CREATE TABLE `film` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(10) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `idx_name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `film` (`id`, `name`) VALUES (3,'film0'),(1,'film1'),(2,'film2');
DROP TABLE IF EXISTS `film_actor`;
CREATE TABLE `film_actor` (
`id` int(11) NOT NULL,
`film_id` int(11) NOT NULL,
`actor_id` int(11) NOT NULL,
`remark` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `idx_film_actor_id` (`film_id`,`actor_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `film_actor` (`id`, `film_id`, `actor_id`) VALUES (1,1,1),(2,1,2),(3,2,1);
When I execute
explain select * from film
left join film_actor on film.id = film_actor.film_id
left join actor on actor.id = film_actor.actor_id
where film.id = 1;
The type of each table is as follows
| table | type |
| ---------- | ----- |
| film | const |
| film_actor | ref |
| actor | ALL |
When I execute
explain select * from film
left join film_actor on film.id = film_actor.film_id
left join actor on actor.id = film_actor.actor_id
The type of each table is as follows
eq_ref is interpreted as One row is read from this table for each combination of rows from the previous tables.
ref is interpreted as All rows with matching index values are read from this table for each combination of rows from the previous tables.
But the difference between these two queries is only a where condition, and no related fields are modified. Why are the types of film_actor and actor tables completely different in the two queries? How to understand this phenomenon?
Thanks in advance.

how to apply one-many and many-one annotations(Java Persistence)

I have two tables as follows:
table1:
CREATE TABLE `Product` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`typename` varchar(255) DEFAULT NULL,
`typecode` varchar(55) DEFAULT NULL,
) ENGINE=InnoDB AUTO_INCREMENT=396 DEFAULT CHARSET=latin1;
table2:
CREATE TABLE measurements (
id int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
age_group varchar(20) NOT NULL,
articleType NOT NULL,
dimension text ,
createdOn int(11) NOT NULL,
updatedOn int(11) NOT NULL,
createdBy text NOT NULL,
)ENGINE=InnoDB AUTO_INCREMENT=396 DEFAULT CHARSET=latin1;
Now how can I join the two tables with join column measurements.articleType = product.typename in Java Persistence.
I know the concept of using one to many and many to one using foreign key(http://en.wikibooks.org/wiki/Java_Persistence/OneToMany). But the above tables does not have foreign key.

I'm here assuming you want a Many-to-Many.
In java, if you want it to be bidirectional, use a
#ManyToMany(mappedBy = "products")
public List<Product> getProducts() { ... }
and in Product
#ManyToMany
#JoinTable(name = "product_measurement")
public List<Measurement> getMeasurement() { ... }
In sql it will be :
CREATE TABLE product_measurement
(
product_measurement_id int(11) NOT NULL,
measurement_product_id int(11) NOT NULL,
FOREIGN KEY (measurement_product_id) REFERENCES measurement (id),
FOREIGN KEY (product_measurement) REFERENCES product (id)
);

You could use JPQL or HQL Native SQL to achieve that. To use Query or Named Query you need to associate the entities together.
Since it is not possible in your case, the Native SQL is the only option.
But consider creating constraints between tables to preserve the data integrity.

how to specify length of the column values whil creating a table in PostgreSQL?

This is how I tried to create table:
CREATE TABLE namevalues
(
seqid integer NOT NULL,
name text(50) NOT NULL,
value text(50),
CONSTRAINT namevalues_pkey PRIMARY KEY (seqid, name)
);
I tried doing this but this doesn't work. could anyone please tell how should I specify the length?

The TEXT type in PostgreSQL does not have a size. You can fix it like this:
CREATE TABLE namevalues
(
seqid integer NOT NULL,
name text NOT NULL,
value text,
CONSTRAINT namevalues_pkey PRIMARY KEY (seqid, name)
);
or use VARCHAR(50) instead of TEXT.

Don't use text, you want varchar...
CREATE TABLE namevalues
(
seqid integer NOT NULL,
name varchar(50) NOT NULL,
value varchar(50),
CONSTRAINT namevalues_pkey PRIMARY KEY (seqid, name)
);
From the PostgreSQL docs...
text: variable unlimited length

Use varchar(50) instead of text(50).
Because,
PostgreSQL API says text data type does't have size, it allow variable with unlimited length
CREATE TABLE namevalues
(
seqid integer NOT NULL,
name varchar(50) NOT NULL,
value varchar(50),
CONSTRAINT namevalues_pkey PRIMARY KEY (seqid, name)
);
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