I'm new to Hibernate and I'm creating a simple movie finder app in Java. I need to make a query in my dao to search movies by a list of keywords. I know how to do it in SQL, but I was wondering if there is any way to make an HQL query to do this. The Java Method in the dao receives a List which is a list of keyowrds and the SQL statement is like this:
SELECT *
FROM movies
WHERE name LIKE '%keyword1%' OR name LIKE 'keyword2' ...
So to achieve this is necessary to iterate trough all the list and concatenate the Query for each keyword.
It's possible to make this query more simple in HQL, so you can pass a list of keywords to que query so it can use it with the LIKE statement?
Thanks.
SELECT *
FROM movies
WHERE name LIKE '%keyword1%' OR name LIKE 'keyword2'
Would translate to HQL as
from movies m where m.name like :keyword1 or m.name like :keyword2
You will need to pass the named parameters keyword1 and keyword2 when querying.
And if you insist of using the like matchers, you will need to loop over the list and dynamically generate the query.
The other option is to actually use the IN clause with the HQL, that would however make wildcard matches impossible.
from movies m where m.name in (:keywords)
Query qry = session.createQuery("From RegistrationBean as rb where rb."+searchCriteria+" like :sf");
qry.setString("sf",'%'+searchField+'%');
Not only did I need to do this, but I needed to do it in a #Query annotation in Spring Data. This is the only way I got it to work. (Keep in mind that this is in an interface.)
#Query(value="from Movie h where lower(h.name) like concat('%',lower(:term),'%'")
List<Movie> findLike(#Param("term") String term);
I put the calls to lower() to make it case-insensitive, and I used the concat() function to add the % characters. It didn't work when I wrote it like this:
#Query(value="from Movie h where lower(h.name) like lower(%:term%)")
List<Movie> findLike(#Param("term") String term); // Query doesn't work! Use concat()
It didn't even work like this, without case sensitivity:
#Query(value="from Movie h where h.name like %:term%")
List<Movie> findLike(#Param("term") String term); // Query doesn't work! Use concat()
Related
How can i write dynamic SQL query in Jbdi, like in my project customer will ask some details like first name,last name,mobile. so i will read those values into string and my idea was directly append that to SQL query dynamically like
select first name,last name,mobile from customer
and another user ask only first name then my query will change like
select first name from customer where customer Id=12345
I am doing something similar for dynamically generated search criteria strings in a Dropwizard application using JDBI.
#UseStringTemplate3StatementLocator
public interface ThingieDao {
#SqlQuery
#MapResultAsBean
Iterator<Thingie> search(#Define("criteria") String criteria);
}
The defined string "criteria" can then be used in the SQL template:
group ThingieDao;
search(criteria) ::= <<
SELECT * FROM table_name WHERE <criteria>
>>
You can use the same technique to insert any string in the SQL, the SELECT column names in your case.
The variable name in the interface does not matter, it is the #Define annotation string that matters.. Assuming Dropwizard doesn't add anything magic, and it usually doesn't, I guess that should work using plain JDBI as well.
In my Case after getting a certain list I need to to iterate that list to set some other fields of the POJO class.
if (transportHeaderList.get(i) instanceof TransportHeaderIiss){
transHeadIiss=(TransportHeaderIiss)transportHeaderList.get(i);
customerVendor= tOManagementDAO.getVendorCode(transHeadIiss.getCustVendUid());
}
if(customerVendor!=null){
transHeadIiss.setVendorCode(customerVendor.getCustVendCode());
}
The Above code calls getVendorCode method to get custVendorCode value from the database. The code for getVendorCode is as follows
public CustomerVendorIiss getVendorCode(Long custVendUid) {
List list=new ArrayList();
/* Criteria criteria = sessionFactory.getCurrentSession().createCriteria(CustomerVendorIiss.class);
criteria.add(Restrictions.eq("companyCode",user.getDefaultCompany().getCompanyCode()));
if(custVendUid!=null && custVendUid.intValue()>0)
{
criteria.add(Restrictions.eq("custVendUid",custVendUid));
}
list=criteria.list();*/
UsersIiss user= ApplicationContextProvider.getLoggedInUser();
String sqlQuery="select custVendCode as custVendCode from CustomerVendorIiss where companyCode ='"+ user.getDefaultCompany().getCompanyCode() +"' and custVendUid= "+custVendUid;
Query query = sessionFactory.getCurrentSession().createQuery(sqlQuery);
query.setResultTransformer(Transformers.aliasToBean(CustomerVendorIiss.class));
list=query.list();
if(list.size()>0){
return (CustomerVendorIiss)list.get(0);
}else{
return null;
}
}
When I executed above code with criteria, it took a lot time to get the values from table and set it to POJO class and sometimes I would get java.lang.OutOfMemoryError: Java heap space error . I guess that's because I am not de-allocating the criteria object.
when I executed the above code using createQuery() method I did not run into that issue and all that process of getting and setting was faster.
I want to understand what is that I am doing wrong here?
it would be great to know how and when criteria is better or HQL is better ?
Thank you !!
Actually these queries are different. The second one has an additional restriction
companyCode ='"+ user.getDefaultCompany().getCompanyCode() +"'
So try to add the same to the criteria
criteria.add(Restrictions.eq("companyCode",user.getDefaultCompany().getCompanyCode()));
Also it's not god to concate strings this way to get the query. SQL injection is possible. Use parameters instead.
Criteria and HQL is better than SQL in one case - you need DB independent logic to swap DB when necessary without rewriting code.
In a spring mvc app using hibernate and MySQL, I have written the following query method to return a list of names with patients:
#SuppressWarnings("unchecked")
public Collection<Person> findPersonByLastName(String ln) throws DataAccessException{
Query query = this.em.createQuery("SELECT DISTINCT pers FROM rimPerson pers left join fetch pers.names nm WHERE nm.family LIKE :lnm");
query.setParameter("lnm", ln);
return query.getResultList();
}
This is producing the following hibernate sql:
Hibernate:
select distinct
person0_.hppid as hppid1_340_0_,
names1_.HJID as HJID1_89_1_,
person0_2_.classCode_HJID as classCod2_339_0_,
person0_1_.administrativeGenderCode_HJID as administ2_341_0_,
person0_1_.birthTime_HJID as birthTim3_341_0_,
names1_.DELIMITER_ as DELIMITE2_89_1_,
names1_.FAMILY as FAMILY3_89_1_,
names1_.named_entity_hppid as named5_89_1_,
names1_.SUFFIX as SUFFIX4_89_1_,
names1_.name_entity_HJID as name9_340_0__,
names1_.HJID as HJID1_89_0__
from
rim_person person0_ inner join rim_living_subject person0_1_ on person0_.hppid=person0_1_.hppid
inner join rim_entity person0_2_ on person0_.hppid=person0_2_.hppid
inner join rim_infrastructure_root person0_3_ on person0_.hppid=person0_3_.hppid
left outer join EN names1_ on person0_.hppid=names1_.name_entity_HJID
where names1_.FAMILY like ?
When I call the above jpql method with the following command, it returns zero results:
this.myappService.findPersonByLastName("");
I also get zero results when I cut and past the above generated hibernate code into the MySQL command line client and replace ? with ''.
If, however, I remove the where names1_.FAMILY like ? from the hibernate generated sql above and place the shortened sql into the MySQL command line client, I get four results, eachof which has a value for the lastname field.
How can I change the jpql so that it generates a hibernate query that returns the four results when `` is passed as the empty string parameter? I want the result set to include every result when the user gives empty input, but to give filtered results when the user types in any given text input.
The typical reason that like fails to do what you think it ought to do is to forget to put a wildcard in the pattern string. For example, if you want to match all user names that begin with 'Code' you must do something like name like 'Code%', NOT name like 'Code'. You can control exactly what your predicate matches with careful placement of %s in your string.
Try this to see all entities no matter what the value in family:
this.myappService.findPersonByLastName("%");
It is kinda cheesy to have the caller of findPersionByLastName have to put in the % wildcard. A better implementation is to have the caller specify which last name they are looking for, and then have the code that constructs the query put the wildcard in the right place. When you are looking for last names, you might do something like this:
query.setParameter("lnm", "%" + ln);
That would match anything that ends with the parameter that is passed to the method.
Note: This may be a simple question but I can't find a short way to make it clear. So, sorry for this long question.
In a project I am responsible, I use Spring 2.5, Hibernate 3.3.2 as middleware and Oracle database. As database is related to many other projects, some queries as really very complicated and I can't get a solution with Hibernate's solutions (HQL, Criteria, etc...). So I feel more comfortable with JdbcTemplate's queryForX() methods, as an example;
String sql = "select * from myTable";
jdbc.queryForList(sql);
Sure there are mostly "where" conditions and params indeed:
jdbc.querForList(sql, new Object[]{obj1,obj2,obj3 /* and many more arguments... */})
In this case, I must write question marks "?" for my parameters, so my SQL query string turns out some messy and hard to read; something like this:
select t1.col1, t2.col2, t1.col, --...some cols ,
sum(nvl(some_col1,?)-nvl(other_col2,?)) over (partition by col1,col2,col3,col4) sum_of_cols
from weird_table t1, another_table t2
where t1.col20=? and sum_of_cols>? and t1.col3=t2.col3 --and many ?'s...
and not exists (
select ? from boring_table t3 where -- many ?'s
)
--group by and order by order by etc
So now, which question mark is for which parameter? It is obvious but hard to read. But there are some other solutions for binded params like:
select * from a_table t where t.col1= :col1 and t.col2= :col2 -- and many more ":param"s
For this type query, we can write if it were Hibernate:
Query q = hibernateTemplate.createQuery();
q.setString("col1","a value");
q.setInteger("col2", 3);
I think it is more readable and easy to understand which value is what. I know I can do this with SQLQuery;
SQLQuery sq = hibernateTemplate.createSQLQuery();
/* same as above setInteger() etc. */
But this sq.list() gives me a list without a column name. so I have a basic array which is difficult to use:
[[1,2,"a"],[1,2,"b"], ...]
But with queryForList() I get better one:
[{COL1=1,COL2=2,COL3="a"},{COL1=1,COL2=2,COL3="b"},...]
So if I use queryForList(), I must write a very messy params Object;
or I use SQLQuery and then I have to get my list without a map as column names.
Is there a simple solution with mapped list using more readable param setting (like query.setX()) ?
Well you can use NamedParameterJdbcTemplate to do just that
Heres a sample
String query = "INSERT INTO FORUMS (FORUM_ID, FORUM_NAME, FORUM_DESC)
VALUES (:forumId,:forumName,:forumDesc)";
Map namedParameters = new HashMap();
namedParameters.put("forumId", Integer.valueOf(forum.getForumId()));
namedParameters.put("forumName", forum.getForumName());
namedParameters.put("forumDesc", forum.getForumDesc());
namedParameterJdbcTemplate.update(query, namedParameters);
You check the complete example with the source code in the below link
Spring NamedParameterJdbcTemplate Tutorial
IN EJB-QL I am trying to create a query like this:
SELECT *
FROM table
WHERE id IN ([id1],[id2],[id3],...);
This is a normal query for oracle or mysql but how can I make EJB-QL set parameters as a list?
SELECT o
FROM ClassName
WHERE ClassNameId IN (List<Long> listOfIds);
is there a way to do this?
More importantly is would this be more efficient then running a separate query for each id in the list?
Any suggestions would be appreciated.
Edit: For clarity I am trying to run one query to return multiple rows based on a list of ids (not the entire table, not the contents of another table, but an arbitrary list of ids). I am hoping to be able to run this query once instead of running a normal find query multiple times (once for each of the ids in the list).
Thanks,
Jim
String queryStr = "select o from ClassName o where o.classNameId IN :ids";
Query query = entityManager.createQuery("queryStr");
List<Long> listOfIds = getIds();
query.setParameter("ids", listOfIds);
List<ClassName> classNameList = (List<ClassName>) query.getResultList();
I'm not an expert with EJB-QL. You might find the examples from here useful.
SELECT OBJECT (o) FROM Order AS o IN (o.lineItems) li
WHERE li.quantity = ?1