CODEWITHSUNDEEP
javadatabasehibernateexceptionjpa
Biscuit128
Biscuit128

Reputation: 5398

Basic Hibernate Select all Syntax

I am trying to retrieve data from my database with hibernate but it keeps throwing an exception

2012-11-11 11:35:45,943 [main] ERROR com.storage.hibernate.DatabaseAccessRequestsImpl - there was an error javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not execute query

@Override
public List<Trade> requestPeriod() {
    List<Trade> trades = null;
    EntityManager manager = emf.createEntityManager();
    Query query = manager.createQuery("from trade"); 
    try{
        trades = query.getResultList();
    }
    catch(PersistenceException e){
        logger.error("there was an error " + e);
    }
    catch(SQLGrammarException e){
        logger.error("there was an error " + e);
    }
    return trades;
}

I am guessing the syntax I am using for select all is incorrect but after looking around I can not see an alternative?

Thanks

Upvotes: 3

Views: 8343

Answers (2)

guido
guido

Reputation: 19194

It should be "from Trade" (uppercase T) as Trade is the name of the mapped class.

Upvotes: 10

Tomasz Nurkiewicz
Tomasz Nurkiewicz

Reputation: 340733

Note that in JPA QL SELECT clause is mandatory, as per: 10.2.1.1. JPQL Select Statement:

A select statement is a string which consists of the following clauses:

  • a SELECT clause, which determines the type of the objects or values to be selected;

  • a FROM clause, which provides declarations that designate the domain to which the expressions specified in the other clauses of the query apply;

[...]

In BNF syntax, a select statement is defined as:

select_statement ::= select_clause from_clause [where_clause] [groupby_clause] [having_clause] [orderby_clause]

The bare from Trade syntax is Hibernate-specific, to be specification compliant you should always use:

select t from Trade t

Upvotes: 6

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