Getting error when mapping PostgreSQL LTREE column in hibernate

Question

I am trying to map postgresql ltree column in hibernate as follows:

In entity :

private String path;

@Column(name="org_path", columnDefinition="ltree")
public String getPath() {
   return path;

Table structure:

CREATE TABLE relationship (
    relationship_id int4 NOT NULL,
    parent_organization_id uuid NOT NULL,
    child_organization_id uuid NOT NULL,
    org_path ltree NOT NULL,
    CONSTRAINT relationship_pk PRIMARY KEY (relationship_id),
    CONSTRAINT organization_fk3 FOREIGN KEY (parent_organization_id) REFERENCES organization(organization_id) ON DELETE RESTRICT ON UPDATE RESTRICT,
    CONSTRAINT organization_fk4 FOREIGN KEY (child_organization_id) REFERENCES  organization(organization_id) ON DELETE RESTRICT ON UPDATE RESTRICT
)

Getting the following error:

wrong column type encountered in column [org_path] in table [relationship]; found [“schemaName"."ltree" (Types#OTHER)], but expecting [ltree (Types#VARCHAR)]

Can anyone help how to resolve this issue?

score 7 · Accepted Answer · edited Dec 29 '16 at 15:03

Implement a custom LTreeType class in Java as follows:

public class LTreeType implements UserType {

    @Override
    public int[] sqlTypes() {
        return  new int[] {Types.OTHER};
    }

    @SuppressWarnings("rawtypes")
    @Override
    public Class returnedClass() {
        return String.class;
    }

    @Override
    public boolean equals(Object x, Object y) throws HibernateException {
        return x.equals(y);
    }

    @Override
    public int hashCode(Object x) throws HibernateException {
        return x.hashCode();
    }

    @Override
    public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
            throws HibernateException, SQLException {
        return rs.getString(names[0]);
    }

    @Override
    public void nullSafeSet(PreparedStatement st, Object value, int index)
            throws HibernateException, SQLException {
        st.setObject(index, value, Types.OTHER);
    }

    @Override
    public Object deepCopy(Object value) throws HibernateException {
        return new String((String)value);
    }

    @Override
    public boolean isMutable() {
        return false;
    }

    @Override
    public Serializable disassemble(Object value) throws HibernateException {
        return (Serializable)value;
    }

    @Override
    public Object assemble(Serializable cached, Object owner)
            throws HibernateException {
        return cached;
    }

    @Override
    public Object replace(Object original, Object target, Object owner)
            throws HibernateException {
        // TODO Auto-generated method stub
        return deepCopy(original);
    }

}

And annotate the Entity class as follows:

    @Column(name = "path", nullable = false, columnDefinition = "ltree")
    @Type(type = "LTreeType")
    private String path;

Does this custom type implicitly getting picked up while persisting with the respective entities? I mean, does hibernate locates and loads the class specified by "type" if its implemented by "UserType"? Or, does the custom type need to be introduced to Hibernate in some way? To me, it does not seem to get picked up, until I used "org.hibernate.boot.model.TypeContributor" to introduce my custom type. — Raj, Jan 15 '19 at 03:25
@Raj or you can use `@Type(type = "com.my.package.LTreeType")` — Jan Mares, Mar 25 '19 at 16:15
@Raj or one more way, put `@TypeDef(name = "ltree", typeClass = LTreeType.class)` on the entity class and then `@Type(type="ltree")` — Jan Mares, Mar 28 '19 at 13:05

score 1 · Answer 2 · answered Oct 13 '17 at 20:21

I had fits until I also created an LQueryType just like the class @arnabbiswas provided for LTreeType. My code only knows about Strings, but Postgres does not know how to use ltree with Strings. The types and operations are:

ltree ~ lquery
ltree @> ltree

So my Kotlin JPA is like this:

val descendantIds = treeRepo.findAllDescendantIds("*.$id.*{1,}")
. . .
@Query(
    "SELECT node_id FROM tree WHERE path ~ CAST(:idQuery AS lquery);"
    , nativeQuery = true)
fun findAllDescendantIds(@Param("idQuery") idQuery: String): Array<Long>

score 1 · Answer 3 · answered May 16 '19 at 16:42

just add this modifications on @anarbbswas code and then it will work fine

 @Override
public Object nullSafeGet(ResultSet rs, String[] names,SharedSessionContractImplementor session, Object owner)
        throws HibernateException, SQLException {
    return rs.getString(names[0]);
}

@Override
public void nullSafeSet(PreparedStatement st, Object value, int index, SharedSessionContractImplementor session) throws HibernateException, SQLException {
    st.setObject(index, value, Types.OTHER);
}

@Override
public Object deepCopy(Object value) throws HibernateException {
    if (value == null)
        return null;
    if (! (value instanceof String))
        throw new IllegalStateException("Expected String, but got: " + value.getClass());
    return value;
}

Getting error when mapping PostgreSQL LTREE column in hibernate

3 Answers3

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