query-by-example.adoc

Running an Example

In Spring Data JDBC, you can use Query by Example with Repositories, as shown in the following example:

Example 1. Query by Example using a Repository

public interface PersonRepository
        extends CrudRepository<Person, String>,
        QueryByExampleExecutor<Person> { … }

public class PersonService {

  @Autowired PersonRepository personRepository;

  public List<Person> findPeople(Person probe) {
    return personRepository.findAll(Example.of(probe));
  }
}

Note	Currently, only SingularAttribute properties can be used for property matching.

The property specifier accepts property names (such as firstname and lastname). You can navigate by chaining properties together with dots (address.city). You can also tune it with matching options and case sensitivity.

The following table shows the various StringMatcher options that you can use and the result of using them on a field named firstname:

Table 1. StringMatcher options

Matching	Logical result
DEFAULT (case-sensitive)	firstname = ?0
DEFAULT (case-insensitive)	LOWER(firstname) = LOWER(?0)
EXACT (case-sensitive)	firstname = ?0
EXACT (case-insensitive)	LOWER(firstname) = LOWER(?0)
STARTING (case-sensitive)	firstname like ?0 + '%'
STARTING (case-insensitive)	LOWER(firstname) like LOWER(?0) + '%'
ENDING (case-sensitive)	firstname like '%' + ?0
ENDING (case-insensitive)	LOWER(firstname) like '%' + LOWER(?0)
CONTAINING (case-sensitive)	firstname like '%' + ?0 + '%'
CONTAINING (case-insensitive)	LOWER(firstname) like '%' + LOWER(?0) + '%'