I am using hibernate with MySQL Db. I have a table of business with some fields and relations. in relations, one relation is optional.
#ManyToOne(fetch = FetchType.LAZY)
#NotFound(action=NotFoundAction.IGNORE)
#JoinColumn(name = "modified_by", nullable = true)
public Users getModifiedBy() {
return this.modifiedBy;
}
public void setModifiedBy(Users modifiedBy) {
this.modifiedBy = modifiedBy;
}
now when I fetch data using the following hql it work fine
String hql = "from Business";
Query query = session.createQuery(hql);
list = query.list();
if i changed hql to the following then it shows 0 result.
String hql = "select new com.ba.Business(business.businessId,business.slUsersByCreatedBy.userId,business.modifiedBy.userId,business.bizType.bizTypeId) from com.ba.Business business order by business.businessName";
How to manage this as modifiedBy is null. There were different solution available which i tried like setting optional to true and setting #NotFound but nothing worked.
SQL Created by hql is following.
select business0_.business_id as col_0_0_, business0_.createdBy as col_1_0_, business0_.modified_by as col_5_0_, business0_.biz_type_id as col_9_0_ from _business business0_, _users users1_, _users users4_, _biz_type biztype7_ where business0_.createdBy= users1_.web_user_id and business0_.modified_by= users4_.web_user_id and business0_.biz_type_id= biztype7_.biz_type_id order by business0_.business_name
it is using "and" for joins. If i explicitly add joins by adding following with hql then the result remain same.
left join business.modifiedBy modifiedBy
Is there any solution available?
When you use business.modifiedBy in the query, it implicitly converts to inner join, and that's why you don't get any results. Change it to this and it should work
String hql = "select new com.ba.Business(business.businessId, business.slUsersByCreatedBy.userId, mb.userId, business.bizType.bizTypeId) from com.ba.Business business left join business.modifiedBy mb order by business.businessName";
Related
I have User class like this:
{
...
Long userID;
...
List<UserMovieRole> userMovieRoles=...
}
A Movie class like this:
{
...
Long movieID;
...
List<UserMovieRole> userMovieRoles=...
}
I have another class UserMovieRole like this:
{
Long userMovieRoleID;
Role role;
...
User user;
...
Movie movie;
}
Now I want to query on UserMovieRole and select where userID and movieID is given.
In sql I can simply write, I can simply write a join and where sql to select.
But in spring boot jpa query, it seems I can't do that, how can I do that?
Here is what I have tried:
#Query("select umr from UserMovieRole umr where umr.user.userID=?1 and umr.movie.movieID=?2")
#Query("select umrj from UserMovieRole.user full join UserMovieRole.movie umrj where umrj.userID=?1 and umrj.movieID=?2")
I dont't know if any of these are correct, what is the actual way of doing it ?
Write a query as you would in SQL in the #Query and then add another property of the annotation as nativeQuery = true and it will run the query as you would in sql.
Pass the parameters in query by adding a : in front of them. Also, don't forget to add #Param in your auguments.
Something like this:
#Query(value = "select umr from UserMovieRole umr join user u on u.id = umr.userId where u.userId (#got it by joining tables.) = :userId and umr.movieID=:movieId", nativeQuery = true)
returnType yourMethod(#Param("userId") userId, #Param("movieId") movieId);
Is it possible with help of SqlResultSetMapping and entityManager.createNativeQuery fetch object with One2Many relations from two different tables ?
For example
#Entity
#Table(name = "posts")
public class Post {
#OneToMany(mappedBy = "post")
private List<Comment> comments;
}
#Entity
#Table(name = "comments")
public class Comment {
#ManyToOne(optional = false)
#JoinColumn(name = "post_id", referencedColumnName = "post_id")
private Post post;
}
Query:
select p.*, c.* from posts p left join (
select * from comments where content like "%test%" order by last_edited limit 0, 3)
as c on p.post_id = c.post_id
based on native sql query I need to fetch posts objects with a comments.
I mean - as a result I need to receive List of Posts and each post of this list is already populated with an appropriate Comments.
Is it possible with JPA ? If so, could you please show an example ?
I know this question is old, but I still had trouble finding an answer, therefore adding one here.
Yes, it is not possible without additional mapping. The result will be a list of Object arrays. The problem is that the list of comments in your case won't be filled automatically. You need to do the mapping yourself.
Let's imagine your return is a resultset like this:
postid
postCommentId
postComment
1001
2001
comment content 1
1001
2002
comment content 2
1999
2999
comment content 1
1001
2003
comment content 3
1001
2004
comment content 4
In the list, you can see two posts. One with 4 comments and one with 1. The SqlResultsetMapping will only map each row as an object array, which means the post.comments list won't be filled. You have to do it manually.
Here is a sample of how you could do it.
List<Object[]> resultList = em.createQuery(query).getResultList();
// prepare a hashmap for easier mapping
final Map<Long, Post> mappedResult = new HashMap<>(resultList.size());
resultList.forEach(o -> {
Post p = (Post) o[0];
Comment c = (Comment) o[1];
var processedPost = mappedResult.get(p.getId());
if(processedPost != null) {
processedPost.addComment(c);
} else {
p.addComment(c);
mappedResult.put(p.getId(), p);
}
});
// return a sorted list from the created hashmap
return mappedResult.values().stream().sorted((p1, p2) -> p1.getId().compareTo(p2.getId())).toList();
I am pretty sure there are better and more performant possibilities, but I was not able to find any.
You can do something like this:
SELECT post from Post post
LEFT JOIN FETCH post.comments -- to fetch all comments in each post
LEFT JOIN FETCH post.comments comment -- to do the WHERE
WHERE comment.content like "%test%"
The problem is the order by last_edited. I think you cannot order the fetched list of comments in JPA, but you can put this annotation in the private List<Comment> comments; to set a default order in the collection:
#OneToMany(mappedBy = "post")
#OrderBy("lastEdited asc")
private List<Comment> comments;
And, finally, to the limit, use the methods firstResult and maxResults from JPA:
return em.createQuery(query)
.setFirstResult(0) // offset
.setMaxResults(3) // limit
.getResultList();
I want to to retrieve data from table in the order of the database table's column order.
Suppose my sql query is
String sql_string = "select * "
+ "from CUSTOMER_INFO "
+ "order by customer_last_name, customer_first_name";
Session session = factory.openSession();
Transaction tx = session.beginTransaction();
List<Map<String,Object>> results = session.createSQLQuery(sql_string)
.setResultTransformer(AliasToEntityMapResultTransformer.INSTANCE)
.list();
In database, the table's column order is like A,B,C,D.
But when I retrieve the data and iterate through it, the entrySet is like C,A,D,B. (int,float,float,String)
I think the data is being retrieved based on its datatype.
I need the retrieved entrySet in the same order as it exists in database's table.
I also tried specifying the column names in select query which was of no use.
CUSTOMER_INFO is model class mapped to sqllite through hibernate.
#Entity
#Table(name = "CUSTOMER_INFO")
public class CustomerInfo{
#Column
private int C;
#Column
private float A;
#Column
private String B;
#Column
private float D;
//getters and setters
}
Using Sqllite 3.6, hibernate, JSP.
Any help is appreciated.
The following SQL script works in mysql:
select
LOGGING_ID,
SUM(NORMAL_HOURS +OVERTIME_HOURS +DOUBLE_TIME_HOURS) AS TOTAL_HOURS
FROM
LOGGING_DETAIL
GROUP BY 1
How would I do this with my entity manager?:
#PersistenceContext
private EntityManager database;
List<loggingDetail> loggingDetail = new ArrayList<loggingDetail>();
timeLoggingDetail = database.createQuery("").getResultList();
at the end I want the Logging_id and the total hours for that ID.
Thanks
The entity manager could called a named query that you set on your jpa entity object. I am assuming you have an entity object in this case. I suppose if you don't have that object you could do it in the query like you have it laid out in your question. I like having it in the entity object though so other calls can re-use it.
Entity object -
#Entity
#NamedQuery( name = "loggingDetail.getLoggingId", query = "select
LOGGING_ID,SUM(NORMAL_HOURS +OVERTIME_HOURS +DOUBLE_TIME_HOURS) AS TOTAL_HOURS
FROM LOGGING_DETAIL GROUP BY 1" )
public class LoggingDetail
{ ...}
The entity manager call will not get a fully populated loggingDetail object back since the query is not returning a full object, so you have to loop through an object array -
#PersistenceContext
private EntityManager database;
Query query = database.createNamedQuery( "loggingDetail.getLoggingId" );
List<Object[]> obj = query.getResultList();
for( Object[] objects : obj )
{
String logId = (String) objects[0] ;
String logTime = (String) objects[1] ;
}
so here is my issue:
i have 3 tables:
ROLE : RID ,NAME
CLIENT : CID, NAME
USER : UID, RID, CID, USERNAME, PASSWORD
Below is the SQL statement that I have written:
SELECT USER.UID,USERNAME,PASSWORD,ROLE.NAME, ROLE.RID
FROM USER
INNER JOIN ROLE ON USER.RID=ROLE.RID
WHERE CID=1;
The above statement is returning only 1 row when there should actually be 2 rows.
I don't understand what is not working.
When i do the following, i get my 2 rows:
SELECT *
FROM USER
WHERE CID =1;
Note that i am using spring framework and also implementing a RowMapper. Below is my actual code with the field names as per the dbase.
public List<User> viewUserClient(int client_id) {
String sql =
"SELECT USER.ID,USERNAME,PASSWORD,ACTIVE,ROLE.NAME, ROLE.ID FROM USER INNER JOIN ROLE ON USER.ROLE_ID=ROLE.ID WHERE CLIENT_ID=?";
List<User> users = this.getJdbcTemplate().query(sql, new Object[] { client_id }, new UserClientRowMapper());
return users;
}
private static final class UserClientRowMapper implements RowMapper<User> {
public User mapRow(ResultSet rs, int rowNum) throws SQLException {
User user = new User();
Client client = new Client();
Role role = new Role();
user.setID(rs.getInt("ID"));
user.setUSERNAME(rs.getString("USERNAME"));
user.setPASSWORD(rs.getString("PASSWORD"));
user.setACTIVE(rs.getBoolean("ACTIVE"));
role.setNAME(rs.getString("NAME"));
role.setID(rs.getInt("ROLE.ID"));
client.setId(rs.getInt("id"));
client.setName(rs.getString("name"));
user.setRole(role);
user.setClient(client);
return user;
}
}
Thanks in advance for your help.
The INNER JOIN keyword returns rows when there is at least one match in both tables. If there are rows in "USER" that do not have matches in "ROLE", those rows will NOT be listed; of the two users returned by your plain select query, probably one has a null RID column value, or a value that is not in ROLE table.
Use a LEFT JOIN.