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I am a noob in Spring framework. I know there is the findAll method to query all the data in a database. Is there a way to count the number of rows in a database using the Spring framework and doesn't require to write a SQL query?
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count() repository method If you want to know the total number of rows available in the entity table, use the count derived method of the CrudRepository interface. For example, the following getCustomerCount method retrieves the number of entities available in the table using the method count.
You can easily do so by using the derived count query available in the CrudRepository since the JpaRepository interface extends the CrudRepositoy . For example, the following countByNewUser is a derived count query. The Customer database contains a new_user column that holds either 0 or 1.
Its findById method retrieves an entity by its id. The return value is Optional<T> . Optional<T> is a container object which may or may not contain a non-null value. If a value is present, isPresent returns true and get returns the value.
Spring Data JPA @Query The @Query annotation declares finder queries directly on repository methods. While similar @NamedQuery is used on domain classes, Spring Data JPA @Query annotation is used on Repository interface. This frees the domain classes from persistence specific information, which is a good thing.
There is method count() in CrudRepository. You can check oficial documentation.
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