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POJPQL issue resolving nodes of a collection to compare in query
 

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  1. POJPQL issue resolving nodes of a collection to compare in query
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    <p>I have a book entity which has a OneToMany relationship set up to Document entity. In other words, in Hibernate, my book entity returns a list of Documents as the property docs.</p> <p>I want to return a list of documents for a user which have not been assigned to a book, yet. Here is my jpql query, and I've finagled it every way I can, and I can't get it to work:</p> <pre><code>select d from Document d WHERE d.user = :user AND NOT EXISTS( SELECT b.docs from Book b WHERE b.docs = d ) </code></pre> <p>Where Book is an entity, User is an entity passed in, b.docs is a list of Documents, and Document(d) is an entity.</p> <p>What am I doing wrong? With this particular version of the query, I'm receiving the error: </p> <blockquote> <p>org.hibernate.TypeMismatchException: left and right hand sides of a binary logic operator were incompatibile [java.util.Collection(com.fallenjusticestudios.bardwalk.model.Book.docs) : com.fallenjusticestudios.bardwalk.model.Document]</p> </blockquote> <p>Book:</p> <pre><code>@Entity @Table(name="book") public class Book { @Id @GeneratedValue(strategy=GenerationType.AUTO) private Long id; @Column @NotEmpty @NotNull private String title; @Column @NotEmpty @NotNull private String description; @ManyToOne(cascade=CascadeType.MERGE, targetEntity=User.class) @JoinColumn(name="user") private User user; @OneToMany(cascade=CascadeType.MERGE, fetch=FetchType.LAZY, targetEntity=Document.class) @JoinColumn(name="document_id",referencedColumnName="id") private List&lt;Document&gt; docs; // Will need to add Contest to the fields later on. // // public Long getId() { return id; } public String getTitle() { return title; } public String getDescription() { return description; } public User getUser() { return user; } public List&lt;Document&gt; getDocs() { return docs; } public void setId(Long id) { this.id = id; } public void setTitle(String title) { this.title = title; } public void setDescription(String description) { this.description = description; } public void setUser(User user) { this.user = user; } public void setDocs(List&lt;Document&gt; docs) { this.docs = docs; } } </code></pre> <p>UPDATE: </p> <p>Another try:</p> <p>Query:</p> <pre><code>select d from Document d WHERE d.user = :user AND NOT EXISTS( SELECT Document from Book.docs b WHERE b.id = dn.id ) </code></pre> <blockquote> <p>org.hibernate.hql.ast.QuerySyntaxException: Book.docs is not mapped [select d from com.fallenjusticestudios.bardwalk.model.Document d WHERE d.user = :user AND NOT EXISTS( SELECT Document from Book.docs b WHERE b.id = dn.id)]</p> </blockquote> <p>UPDATE2:</p> <p>I figured this out. I was going about the query all wrong. Solution query was:</p> <pre><code>select d from Document d WHERE d.user = :user AND NOT d IN( SELECT d from Book b, IN(b.docs) bd WHERE bd.id = d.id ) </code></pre>
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    1. USKyle Richter
    1. USKyle Richter
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