Good day!
I'm using a Criteria Query to build a query to a table, with some predicates, like this:
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery q = cb.createQuery();
Root<Foo> root = q.from(Foo.class);
List<Predicate> predicates = new ArrayList<Predicate>();
[added some predicates]
q.select(root).where(predicates.toArray(new Predicate[]{}));
As you can see, there is nothing strange in this code snippet...but when I build the typed query to get the result list of the query:
TypedQuery<Foo> finalQuery = em.createQuery(q);
List<Foo> result = finalQuery.getResultList();
I get an exception when I run in Weblogic 10.3.5, in the typed query creation line:
weblogic.deployment.QueryProxyImpl cannot be cast to javax.persistence.TypedQuery
I build this entire code snippet based on a Oracle Example, which you can find in this URL: http://docs.oracle.com/javaee/6/tutorial/doc/gjrij.html
What do you think could be the error?
Thanks to everyone!
EDIT: This exception is showed when you haven't put the JPA 2 library in the weblogic classpath. You have to add the next line in your commEnv.sh/commEnv.cmd file:
Linux:
PRE_CLASSPATH=${BEA_HOME}/modules/javax.persistence_1.0.0.0_2-0-0.jar:${BEA_HOME}/
modules/com.oracle.jpa2support_1.0.0.0_2-0.jar
export PRE_CLASSPATH
Windows:
set PRE_CLASSPATH=%BEA_HOME%\modules\javax.persistence_1.0.0.0_2-0-
0.jar;%BEA_HOME%\modules\com.oracle.jpa2support_1.0.0.0_2-0.jar
try writing:
CriteriaQuery<Foo> q = cb.createQuery();
before you had:
CriteriaQuery q = cb.createQuery();
I had similar problem but while creating a namedquery instead of createQuery. Previously it was working fine. But when TransactionAttribute, TransactionAttributeType.Not_SUPPORTED, it is throwing weblogic.deployment.QueryImpl cannot be cast to TypedQuery. When I removed the transaction attribute, it worked!
Related
I want to use criteriaUpdate to create an update query like this:
UPDATE <SOME TABLE>
SET SELECTED = !SELECTED
WHERE
[DYNAMIC QUERY HERE]
The closest I could get was with the code:
public <T> Query createRevertSelectionQuery(Class<T> clazz, EntityManager em, Specification<T> s) {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaUpdate<T> criteriaUpdate = cb.createCriteriaUpdate(clazz);
Root<T> root = criteriaUpdate.from(clazz);
Predicate p = cb.and(new Predicate[] {s.toPredicate(root, null, cb)});
Expression<Boolean> e =cb.not((root.get("selected").as(Boolean.class)));
Path<Boolean> selected = root.get("selected");
criteriaUpdate.set(selected, e);
criteriaUpdate.where(p);
Query q = em.createQuery(criteriaUpdate);
return q;
}
but it fails because I get the following query:
update com.redknee.suspense.mgt.model.Moc as generatedAlias0
set generatedAlias0.selected = generatedAlias0.selected <> true
where
[dynamic query]
giving me the error
org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token: <> near line 1, column 118
Anyone can help please?
I am not sure if this is a bug or if it is just not meant to be used this way .
In where-clause NOT and any other operands work like a charm. But, no matter what you try Hibernate query builder seems always to optimize those parenthesis away (in my opinion it might still be a good habit to always use parenthesis but its only an opinion).
One way to force parenthesis is to use JPA Subquery. See below example. Note that i have slightly altered the JPA object names by my own taste and not included the Specification because it is not relevant to this solution:
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaUpdate<T> update = cb.createCriteriaUpdate(clazz);
Root<T> from = update.from(clazz);
Path<Boolean> selected = from.get("selected");
// Subquery just "joins back" to the same row and
// returns a negated boolean value of "selected" from the original row
Subquery<Boolean> subSelect = update.subquery(Boolean.class);
Root<T> subFrom = subSelect.from(clazz);
subSelect.select(cb.not(selected));
subSelect.where(cb.equal(from.get("id"), subFrom.get("id")));
update.set(selected, subSelect);
I have following issue. I am using Jquery Datatable serverside and I am now implementing the search box. But I have an issue there in special case, when a dataset has an attribute, what is "null". So the dataset will not be found although it should found cos it matches on one attibute.
The situtation in beginning is like follows. You see there is a dataset with apprentice Fabio Bartels, who has not Fachrichtung. And a dataset with Viktoria.
Now when I search for Viktoria, the filter works as expected:
When I search for Fabio, then Dataset is not found:
=====
The problem I have is, that I don't know how to handle the filter, that a attribute will only be validated against the search string when the attribute is not null.
=====
Serverside Java Classes see like follows:
QueryClass:
class ContractSearchQuery {
private static QContract contract = QContract.contract;
static BooleanExpression getPredicate(final ContractSearch filter) {
BooleanExpression predicate;
if (filter == null || filter.isEmpty()) {
// SHOW ALL PREDICATE ...
} else {
final String search = filter.getSearch();
final List<BooleanExpression> expressions = new ArrayList<BooleanExpression>();
// EXPRESSIONS CURRENTLY ONLY ON AUSZUBILDENDER AND FACHRICHTUNG
// FOR SHOWCASE
expressions.add(containsApprenticeName(search)); // AUSZUBILDENDER
expressions.add(containsSpecialisation(search)); // FACHRICHTUNG
BooleanExpression expression = expressions.get(INTEGER_ZERO);
for (int i = 1; i < expressions.size(); i++) {
expression = expression.or(expressions.get(i));
}
predicate = expression;
}
return predicate;
}
private static BooleanExpression containsApprenticeName(final String search) {
final BooleanExpression expLastName = contract.apprentice.lastName.containsIgnoreCase(search);
final BooleanExpression expFirstName = contract.apprentice.firstName.containsIgnoreCase(search);
return expLastName.or(expFirstName);
}
private static BooleanExpression containsSpecialisation(final String search) {
return contract.companyOccupationCombination.occupationCombination.specialisation.name.containsIgnoreCase(search);
}
}
Spring-Data-Repository Call:
final PageRequest pageRequest = new PageRequest(firstResult / maxResults, maxResults, orderSort);
final Page<Contract> page = contractRepository.findAll(predicate, pageRequest);
return page.getContent();
=======
Database:
By the way I recognized when I do direct request against my db with joining Specialisation Table, then I only get Fabio as record, when not joining Specialisation, I get all three persons. Maybe somethings to do with my issue:
select a.first_name, a.last_name from contract c
join company_occupation_combination coc on c.company_occupation_combination = coc.id
join occupation_combination oc on coc.occupation_combination = oc.id
join apprentice a on c.apprentice = a.id
Result:
"Fabio";"Bartels"
"Viktoria";"Kruczek"
"Lina";"Ehleiter"
With Join:
select a.first_name, a.last_name from contract c
join company_occupation_combination coc on c.company_occupation_combination = coc.id
join occupation_combination oc on coc.occupation_combination = oc.id
join specialisation s on oc.specialisation = s.id
join apprentice a on c.apprentice = a.id
Result: "Viktoria";"Kruczek"
====
EDIT:
Okay, on db site I found out (with Hibernate and JPA I start forgetting SQL-Basices ;-)), that I need a left join for the nullable relation, so my query should result to an sql like:
select a.first_name, a.last_name from contract c
join company_occupation_combination coc on c.company_occupation_combination = coc.id
join occupation_combination oc on coc.occupation_combination = oc.id
left join specialisation s on oc.specialisation = s.id
join apprentice a on c.apprentice = a.id
====
So my question is, how can I manage left Join when I have a Query-Class using QueryDSL and Spring-Data-Repository like mentioned above?
If you really need left join, you can't achieve that via predicate (instead it is possible via sub-query)
To be able to do left-join, you will need JPAQuery.
Assuming you have already configured repositories, and able to use EntitiManager, implement ContractRepositoryCustom , so that in your implementation you can have
#PersistenceContext(unitName = "unitname")
protected EntityManager entityManager;
public List<Contract> findAllContracts() {
return new JPAQuery(entityManager, HQLTemplates.DEFAULT)
.from(QContract.contract)
.join(QContract.contract.companyOccupationCombination, QCompanyOccupationCombination.companyOccupationCombination)
.join(QCompanyOccupationCombination.companyOccupationCombination.occupationCombination, QOccupationCombination.occupationCombination)
.leftJoin(QOccupationCombination.occupationCombination.specialization, QSpecialization.specialization)
.join(QSpecialization.specialization.apprentice, QApprentice.apprentice)
.list(QContract.contract);
}
And for pagination you always apply limit(maxResults) and offset(firstResult)
I really like working with Spring-Data and Query-DSL, cos it makes my code really tidy. But I am really suprised, that for the case of nullable references there seems no solution. Sure you can use another solution like #vtorosyan mentioned and thank you again for that solution, but when you project is builded up with combination of QueryDSL and Spring-Data, you really don't want to bring a second style in your application.
But I needed a solution, so I did now the follows.
The point of the issue was, that when I used data from a nullable entity, a join has been executed what hided the datasets, who had a null reference on it, see examples above. What I now did and I hope I will not get another issue then with that solution on later time of that project. I did the null references to not null and defined something like null-record.
Example I added a record for specialisation like
ID NAME
0 Keine
Instead of null I now use that record what has until now following effects:
First my table shows now "Keine" (engl. "None") for all attributes what are not set. It looks more consistent when having a textoutput then empty string.
Now I can explicitly search for "Keine", when I am interested for data records what have no specialisation set.
And my searchbox works as expected for records, which have no speciafication set. (THAT WAS MY ISSUE FROM BEGINNING WHAT I WANTED TO SOLVE):
Additional to that searchbox I use a modal dialog for filtering. Now I can explicitly filter "Keine" for "nullable" records:
If you think there is another good solution for that issue without rebuild code using Spring-Data and QueryDSL konsequently, don't hesitate to post ;-)
I need to enumerate the tables in a Derby (aka Java DB) database using JDBC in a Java program. All I am aware of for doing this is the SHOW TABLES command.
I first tried with something similar to this...
String strConnectionURL = "jdbc:derby:/path/to/derby/database;create=false";
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
Connection connection = DriverManager.getConnection(strConnectionURL);
Statement statement = connection.createStatement();
boolean boResult = statement.execute("SHOW TABLES");
if (boResult) {
System.out.println("yay!");
}
...but that throws an exception:
java.sql.SQLSyntaxErrorException: Syntax error: Encountered "SHOW" at line 1, column 1.
So next I thought maybe I needed to use a CallableStatement so I tried this...
String strConnectionURL = "jdbc:derby:/path/to/derby/db;create=false";
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
Connection connection = DriverManager.getConnection(strConnectionURL);
CallableStatement statement = connection.prepareCall("SHOW TABLES");
boolean boResult = statement.execute();
if (boResult) {
System.out.println("yippee!");
}
...but that throws the same exception:
java.sql.SQLSyntaxErrorException: Syntax error: Encountered "SHOW" at line 1, column 1.
So, can anyone help me enumerate the tables in my Derby (Java DB) database from JDBC?
EDIT: I'm looking around and starting to get a feeling this may be a general JDBC question. In other words, one could/would enumerate all a db's tables with the DatabaseMetaData object that can be retrieved from the Connection object. Looking into that (and looking forward to responses)...
EDIT 2: I found a pure JDBC solution, but am still happy to hear alternatives...
String strConnectionURL = "jdbc:derby:/path/to/db;create=false";
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
Connection connection = DriverManager.getConnection(strConnectionURL);
DatabaseMetaData dbmd = connection.getMetaData();
ResultSet resultSet = dbmd.getTables(null, null, null, null);
while (resultSet.next()) {
String strTableName = resultSet.getString("TABLE_NAME");
System.out.println("TABLE_NAME is " + strTableName);
}
Show Tables is an ij command, not a base SQL statement, so you can't directly execute it. As you noted in your "EDIT 2", you can use the DatabaseMetaData to do this. Two other ways to do it are: you can select from the system catalogs (see http://db.apache.org/derby/docs/10.8/ref/rrefsistabs24269.html) , or you can use the "ij.runScript" method to run the ij tool from within your program, and pass it the "show tables" command (see http://db.apache.org/derby/docs/10.8/publishedapi/jdbc3/org/apache/derby/tools/ij.html)
As Bryan suggested ij.runScript - the code would look like this:
public void showTbls() throws Exception{
String sqlIn = "SHOW TABLES;";
InputStream stream = new ByteArrayInputStream(sqlIn.getBytes(StandardCharsets.UTF_8));
ij.runScript(conn,stream,StandardCharsets.UTF_8.name(), System.out,"UTF-8");
stream.close();
}
assumming conn is a opened derby Connection
But the disadvantage is that you are getting only string output. Not an ResultSet as you would get from:
Statement stmt = conn.createStatement();
ResultSet results = stmt.executeQuery("SELECT * FROM sys.systables");
or if you want only user table names you can use following SQL:
ResultSet results = stmt.executeQuery("SELECT TABLENAME FROM SYS.SYSTABLES WHERE TABLETYPE='T'");
A very similar output to
SHOW TABLES;
can be produced by using the following jdbc compliant query:
SELECT TABLENAME, (SELECT SCHEMANAME
FROM SYS.SYSSCHEMAS
WHERE SYS.SYSTABLES.SCHEMAID = SYS.SYSSCHEMAS.SCHEMAID)
AS SCHEMANAME
FROM SYS.SYSTABLES WHERE TABLETYPE='T'
It also shows you the probably useful SCHEMA information for each TABLE entry. Skip
TABLETYPE='T'
if you also want to see the system tables of your database as the user before has mentioned already.
I'm using a LINQ to CRM from Advanced Developer Extension for MS CRM 4.0. It works fine with direct queries. But I've got a problem when query looks like this:
var connectionString = #"User ID=u; Password=p; Authentication Type=AD; Server=http://crm:5555/UO";
var connection = CrmConnection.Parse(connectionString);
var dataContext = new CrmDataContext(connection);
var data = from u in dataContext.Accounts
select new
{
Id = u.AccountID,
Name = u.AccountName,
};
var r = from n in data
where n.Name.StartsWith("test")
select new
{
Id = n.Id
};
r.Dump();
it throws an InvalidOperationException "Cannot determine the attribute name."
It's fine when a condition is directly in first query:
var data = from n in dataContext.Accounts
where n.AccountName.StartsWith("test")
select new
{
Id = n.AccountID,
Name = n.AccountName,
};
I cannot find any useful information about this kind of error. Is it a bug in Xrm Linq Provider?
Thanks in advance for any help.
Try eager loading the initial query with a ToList() so the latter query over your anonymous type is then evaluated locally. I get this is far from ideal if you have a lot of accounts but it'll prove the point. You essentially have a solution anyway in the last statement.
This is because the first query isn't executed at all until you call .Dump() at which point the entire expression including the second query is evaluated as one (deferred execution) by the provider which then looks for an attribute of Name.
I have the following Linq query:
var tmp =
from container in Container
join containerType in ContainerType on container.ContainerType equals containerType
where containerType.ContainerTypeID == 2
select new { ContainerID = container.ContainerID, TypeID = container.ContainerTypeID};
var results = tmp.Select((row, index) => new { row.ContainerID, row.TypeID, ContainerIndex = index })
As is, this works fine. If I add the following, so I can see the results in LinqPad, I get the error described in the title of this message:
results.Dump();
This error is not a LinqPad error, it's coming from Linq, and I don't understand what it means.
Thank you.
Okay, I hadn't realised Container was a LINQ to SQL data source to start with. Basically it's failing to convert the second projection to SQL.
So, you want to do just that bit in .NET instead - you can force it to use Enumerable.Select with AsEnumerable:
var results = tmp.AsEnumerable()
.Select((row, index) => new { row.ContainerID, row.TypeID,
ContainerIndex = index });