i have a native sql query to transform (aliasToBean) to a bean with a boolean value.
My query can be something like this:
select val IS NOT NULL as boolValue , ...
or this:
select 1=0 as boolValue, ...
I can not understand how to let Hibernate knows that my bean.boolValue is a Boolan because I get errors in type conversion, in the first case I get a java.math.BigInteger in the second a java.lang.Integer.
Thank you.
You need to tell Hibernate that this column is a boolean, with the SQLQuery.addScalar() method.
Related
I am using spring boot and spring data JPA with a Postgres database. There is a weird behaviour that happens when query something and the result is nothing.
In a lot of databases and projects when I make a query and the result was empty the returned object to java was null.
For example:
#Query(value = "select * from notification where WEBCODE = :webCode OR USERNAME = :username", nativeQuery = true)
Page<NotificationSQL> getNotificationsAsPage(#Param( "webCode" ) String webCode,#Param( "username" ) String username, Pageable pageable);
In this case I was suppose to get a null page. but in this case I am receiving an exception
org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:259)
...
Caused by: org.postgresql.util.PSQLException: ERROR: operator does not exist: character varying = bytea
Hint: No operator matches the given name and argument types. You might need to add explicit type casts.
Position: 42
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2552)
I do not understand why it does not just return a null object. It happens the same with the rest of the queries when empty rows and different objects as List classes. In a lot of projects this has not happen to me, the returned object when the query was right and empty rows was a null.
If the parameters are not null it works perfect, but the point is that these parameters sometimes are null and , as it can be seen in the image, the query works nice but with a result of empty rows.
Thanks in advance
In slick 3 with postgres, I'm trying to use a plain sql query with a tuple column return type. My query is something like this:
sql"""
select (column1, column2) as tup from table group by tup;
""".as[((Int, String))]
But at compile time I get the following error:
could not find implicit value for parameter rconv: slick.jdbc.GetResult[((Int, String), String)]
How can I return a tuple column type with a plain sql query?
GetResult[T] is a wrapper for function PositionedResult => T and expects an implicit val with PositionedResult methods such as nextInt, nextString to extract positional typed fields. The following implicit val should address your need:
implicit val getTableResult = GetResult(r => (r.nextInt, r.nextString))
More details can be found in this Slick doc.
Oracle DB.
Spring JPA using Hibernate.
I am having difficulty inserting a Clob value into a native sql query.
The code calling the query is as follows:
#SuppressWarnings("unchecked")
public List<Object[]> findQueryColumnsByNativeQuery(String queryString, Map<String, Object> namedParameters)
{
List<Object[]> result = null;
final Query query = em.createNativeQuery(queryString);
if (namedParameters != null)
{
Set<String> keys = namedParameters.keySet();
for (String key : keys)
{
final Object value = namedParameters.get(key);
query.setParameter(key, value);
}
}
query.setHint(QueryHints.HINT_READONLY, Boolean.TRUE);
result = query.getResultList();
return result;
}
The query string is of the format
SELECT COUNT ( DISTINCT ( <column> ) ) FROM <Table> c where (exact ( <column> , (:clobValue), null ) = 1 )
where "(exact ( , (:clobValue), null ) = 1 )" is a function and "clobValue" is a Clob.
I can adjust the query to work as follows:
SELECT COUNT ( DISTINCT ( <column> ) ) FROM <Table> c where (exact ( <column> , to_clob((:stringValue)), null ) = 1 )
where "stringValue" is a String but obviously this only works up to the max sql string size (4000) and I need to pass in much more than that.
I have tried to pass the Clob value as a java.sql.Clob using the method
final Clob clobValue = org.hibernate.engine.jdbc.ClobProxy.generateProxy(stringValue);
This results in a java.io.NotSerializableException: org.hibernate.engine.jdbc.ClobProxy
I have tried to Serialize the Clob using
final Clob clob = org.hibernate.engine.jdbc.ClobProxy.generateProxy(stringValue);
final Clob clobValue = SerializableClobProxy.generateProxy(clob);
But this appears to provide the wrong type of argument to the "exact" function resulting in (org.hibernate.engine.jdbc.spi.SqlExceptionHelper:144) - SQL Error: 29900, SQLState: 99999
(org.hibernate.engine.jdbc.spi.SqlExceptionHelper:146) - ORA-29900: operator binding does not exist
ORA-06553: PLS-306: wrong number or types of arguments in call to 'EXACT'
After reading some post about using Clobs with entities I have tried passing in a byte[] but this also provides the wrong argument type (org.hibernate.engine.jdbc.spi.SqlExceptionHelper:144) - SQL Error: 29900, SQLState: 99999
(org.hibernate.engine.jdbc.spi.SqlExceptionHelper:146) - ORA-29900: operator binding does not exist
ORA-06553: PLS-306: wrong number or types of arguments in call to 'EXACT'
I can also just pass in the value as a String as long as it doesn't break the max string value
I have seen a post (Using function in where clause with clob parameter) which seems to suggest that the only way is to use "plain old JDBC". This is not an option.
I am up against a hard deadline so any help is very welcome.
I'm afraid your assumptions about CLOBs in Oracle are wrong. In Oracle CLOB locator is something like a file handle. And such handle can be created by the database only. So you can not simply pass CLOB as bind variable. CLOB must be somehow related to database storage, because this it can occupy up to 176TB and something like that can not be held in Java Heap.
So the usual approach is to call either DB functions empty_clob() or dbms_lob.create_temporary (in some form). Then you get a clob from database even if you think it is "IN" parameter. Then you can write as many data as you want into that locator (handle, CLOB) and then you can use this CLOB as a parameter for a query.
If you do not follow this pattern, your code will not work. It does not matter whether you use JPA, SpringBatch or plan JDBC. This constrain is given by the database.
It seems that it's required to set type of parameter explicitly for Hibernate in such cases. The following code worked for me:
Clob clob = entityManager
.unwrap(Session.class)
.getLobHelper()
.createClob(reader, length);
int inserted = entityManager
.unwrap(org.hibernate.Session.class)
.createSQLQuery("INSERT INTO EXAMPLE ( UUID, TYPE, DATA) VALUES (:uuid, :type, :data)")
.setParameter("uuid", java.util.Uuid.randomUUID(), org.hibernate.type.UUIDBinaryType.INSTANCE)
.setParameter("type", java.util.Uuid.randomUUID(), org.hibernate.type.StringType.INSTANCE)
.setParameter("data", clob, org.hibernate.type.ClobType.INSTANCE)
.executeUpdate();
Similar workaround is available for Blob.
THE ANSWER: Thank you both for your answers. I should have updated this when i solved the issue some time ago. In the end I used JDBC and the problem disappeared in a puff of smoke!
How do I translate the following to a Django database search?
SELECT column1 FROM TABLE 'my_table' WHERE column2 = 'some text'
So far I've tried this, which is the wrong syntax:
my_table.objects.get(column1,column2 = 'some text')
Get the model instance by column2 using get() and retrieve the value of column1 field:
my_table.objects.get(column2='some text').column1
Note that if the object would not be found, get() throws DoesNotExist exception which you probably want to handle separately. Also, if there would be more than one object found, it would throw MultipleObjectsReturned exception, which is also something you need to think about beforehand.
Alternatively, you can use filter() with values():
my_table.objects.filter(column2='some text').values('column1')
This would return a ValuesQuerySet (think about it as a list of dictionaries).
There are a couple of ways out , here is one :
obj = my_table.objects.get(column2="any_item").column1
I have a VO class which has the getter and setter of another VO class too. For example:
Class DocumentVO{
PrintJobVO job;
PrintRunVO run;
String id;
getters and setters..
}
Now I have a requirement to use the Native SQL Query using spring hibernate. When I want to map the ids I have a problem. My query is,
select {r.*},{d.*}
from runs {r}, documents {d}
where {r}.RUN_ID as {r.id} = d.RUN_ID as {d.run.id}
Here run is of type PrintRunVO which has its id and other values. How can I map them in my SQL? I am getting an error like invalid user.table.column, table.column, or column specification.
What's the way to overcome this?
Use the Result Transformer concept in your plain SQL query.
String query = "myquery";
SQLQuery q = session.createSQLQuery(query);
q.addScalar("param1", Hibernate.STRING);
q.addScalar("param2", Hibernate.STRING);
q.setResultTransformer(Transformers.aliasToBean(MyVO.class));
q.setParameter("queryParam1", "some value");
return q.list();