CODEWITHSUNDEEP
javahibernatereverse-engineering
Filipe
Filipe

Reputation: 1219

How to make the hibernate map a created table?

I have tried to model just a few columns for a already created table. But Hibernate can´t perform queries able to return data for the application.

I'm doing something like this in the model that maps a created table:

@Column(name="LOCALE_ID")
private String locale;

@Id
@Column(name="ID")
private Long ID;

@Column(name="TITLE")
private String title;

public Location () {}

public Long getID() {
    return ID;
}

public void setID(Long ID) {
    this.ID = ID;
}

public String getLocale() {
    return locale;
}

public void setLocale(String locale) {
    this.locale = locale;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
    this.title = title;
}

The method that performs the query is shown below:

String q = "SELECT l.title FROM " + className +
            " l WHERE l.locale = '" + locale + '"';
List<Location> result = null;
try {
    Transaction tx = getSession().beginTransaction();
    result = (List<Location>)session.createQuery(q).list();
    tx.commit();
} catch (Exception ex) {
    ex.printStackTrace();
}
return result;

When i called this method with correct parameters, nothing is returned, but the mapped table contains data that can be fetched with those parameters.

I dont know why the hibernate can´t handle with created tables.

Maybe an reverse engineering to generate the model, can help, but i dont know how to perform this.

Any thoughs on this?

Upvotes: 0

Views: 61

Answers (3)

Filipe
Filipe

Reputation: 1219

The best way to perform the search is with constructor expression in the SELECT, see it below:

String q = "Select new " + className + "(l.ID, l.title, l.locale) From " + className + " l Where l.locale = '" + locale + "'";

Upvotes: 0

Uwe Allner
Uwe Allner

Reputation: 3467

You are shadowing your List result in the try/catch block with an equally named, but new variable, to which you assign the results of the query. But you always return the outer variable assigned to null.

String q = "SELECT l.title FROM " + className +
            " l WHERE l.locale = '" + locale;
List<Location> result = null;
try {
    Transaction tx = getSession().beginTransaction();
    result = (List<Location>)session.createQuery(q).list();
    tx.commit();
} catch (Exception ex) {
    ex.printStackTrace();
}
return result;

might do better

Upvotes: 1

Antoniossss
Antoniossss

Reputation: 32535

You should use query ability to specify parameters, as probably this will be the issue. Try something like this

String q = "SELECT l.name FROM yourclassname l WHERE l.locale=:locale";
List<Location> result = null;
try {
    Transaction tx = getSession().beginTransaction();
    session=yourFactory.openSession();
    query=session.createQuery(q);
    query.setParameter("locale",yourLocaleVal);
    result=query.list();
    tx.commit();
} catch (Exception ex) {
    ex.printStackTrace();
}
return result;

Upvotes: 0

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