Substring search a numeric field with JPA/Hibernate - sql

Question

I have a JPA entity that has a numeric field. Something like:
#Basic(optional = false)
#Column(name = "FISCAL_YEAR", nullable = false)
private int fiscalYear;
I have a requirement to sub-string search this field. For example, I want a search for 17 to give me 2017 and 1917 and 1789. Forget for a minute what a crazy request this is and assume I have a real use case that makes sense. Changing the column to a varchar in the database is not an option.
In PL/SQL, I'd covert the field to a varchar and do a like '%17%'. How would I accomplish this with Hibernate/JPA without using a native query? I need to be able to use HQL or Criteria to do the same thing.

Answer 1

Achieving like on numeric values using criteria builders
Table
Employee | CREATE TABLE `Employee` (
`id` int(11) NOT NULL,
`first` varchar(255) DEFAULT NULL,
`last` varchar(255) DEFAULT NULL,
`occupation` varchar(255) DEFAULT NULL,
`year` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
Entity
private Integer year;
public Integer getYear() {
return year;
}
public void setYear(Integer year) {
this.year = year;
}
Data in the table
+----+-------+------+------------+------+
| id | first | last | occupation | year |
+----+-------+------+------------+------+
| 2 | Ravi | Raj | Textile | 1718 |
| 3 | Ravi | Raj | Textile | 1818 |
| 4 | Ravi | Raj | Textile | 1917 |
| 5 | Ravi | Raj | Textile | NULL |
| 6 | Ravi | Raj | Textile | NULL |
| 7 | Ravi | Raj | Textile | NULL |
+----+-------+------+------------+------+
constructing query using criteria builder
public List<Employee> getEmployees() {
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<Employee> q = cb.createQuery(Employee.class);
Root<Employee> emp = q.from(Employee.class);
Predicate year_like = cb.like(emp.<Integer>get("year").as(String.class), "%17%");
CriteriaQuery<Employee> fq = q.where(year_like);
List<Employee> resultList = (List<Employee>) entityManager.createQuery(fq).getResultList();
return resultList;
}
query generated(using show_sql: true)
Hibernate: select employee0_.id as id1_0_, employee0_.first as first2_0_, employee0_.last as last3_0_, employee0_.occupation as occupati4_0_, employee0_.year as year5_0_ from Employee employee0_ where cast(employee0_.year as char) like ?
Query Output
// i have printed only id and year in the console
id, year
2, 1718
4, 1917
------------------------------------------------------------
Alternate way
LIKE worked in JPA for numeric field when Tested with JPA, hibernate, mysql.
Note:- May not work with other jpa providers
Query r = entityManager.createQuery("select c from Employee c where c.year like '%17%'");
query fired(using show_sql=true)
Hibernate: select employee0_.id as id1_0_, employee0_.first as first2_0_, employee0_.last as last3_0_, employee0_.occupation as occupati4_0_, employee0_.year as year5_0_ from Employee employee0_ where employee0_.year like '%17%'
Query Result
// i have printed only id and year in the console
id, year
2, 1718
4, 1917

Answer 2

You can declare your own Criterion type
public class CrazyLike implements Criterion {
private final String propertyName;
private final int intValue;
public CrazyLike(String propertyName, int intValue) {
this.propertyName = propertyName;
this.intValue = intValue;
}
#Override
public String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery)
throws HibernateException {
final String[] columns = criteriaQuery.findColumns( propertyName, criteria );
if ( columns.length != 1 ) {
throw new HibernateException( "Crazy Like may only be used with single-column properties" );
}
final String column = columns[0];
return "cast(" + column + " as text) like '%" + intValue + "%'";
}
#Override
public TypedValue[] getTypedValues(Criteria criteria,
CriteriaQuery criteriaQuery) throws HibernateException {
return new TypedValue[] { };
}
}
And then use it like this:
Criteria criteria = session.createCriteria(Person.class);
List<Person> persons = criteria.add(new CrazyLike("year", 17)).list();
assuming that Person has an int property called year. This should produce a SQL like this:
select
this_.id as id1_2_0_,
this_.birthdate as birthdat2_2_0_,
this_.firstname as firstnam3_2_0_,
this_.lastname as lastname4_2_0_,
this_.ssn as ssn5_2_0_,
this_.version as version6_2_0_,
this_.year as year7_2_0_
from
Person this_
where
cast(this_.year as text) like '%17%'
This was tested with Postgres. The cast() syntax may vary for your database engine. If it is, just use that syntax in the Criterion class that you implement.