![]() ![]() First query returns all employees data, and second one will result all employees for a department id. Here we have defined two named queries getAllEmployees and getAllEmployeesByDeptId. Public class EmployeeEntity implements Serializable "FROM employee, = "getAllEmployeesByDeptId", Query = "SELECT id, firstName, lastName, email, department.id, department.name " + Named SQL native queries are defined like = "getAllEmployees", Like JPQL named queries, the name of the query must be unique within the persistence unit. This annotation may be placed on any entity and defines the name of the query as well as the query text. Named SQL queries are defined using the annotation. You could define this in mapping file in hibernate or also using annotations at entity level. Named query is the way you define your query by giving it a name. These queries are the sql statements which can be directly executed in database using a database client.Ģ. Native query refers to actual sql queries (referring to actual database objects). We will also use named sql native queries in this example.ġ. We will pass in the query string to be executed in underlying database and the entity type that will be returned as result. The assumption is that you will rarely fallback to writing low-level custom code and most of the time you will stick to Spring Data repositories cherishing the features described so far.In this JPA native query example, we will learn to use JPA native query ( SQL SELECT query) using createNativeQuery() method of the EntityManager interface. For such scenarios Spring Data provides a way to strip all the layers of abstractions and get down to writing a more specific implementation. It is very likely, that at one point you will reach a situation where all the above solutions do not work. What’s great about Querydsl is we get autocompletion: Custom repositories In our case Querydsl will generate QEmployee class from the corresponding Employee entity.īelow you can find Maven configuration for generating Q* classes during compilation: Ĭom.Īfter setting it up you can write code like this: QEmployee employee = QEmployee.employee It works by generating special classes prepended with “Q” and based on the entity classes. To enforce a stricter name and type checking Querydsl can be used: One downside of specifications is that they are not strictly typed, meaning we can run into issues when misstyping a property name or if we assume incorrect property type. HasNameLike("LIC").and(hasSalaryAbove(new BigDecimal("8000")))) ![]() The best part is that specifications can be mixed together allowing for better customizability and reusability: repository.findAll( Public Employee(Long id, String name, BigDecimal salary). Kickstarting a project with Spring Data is as simple as adding this dependency: Īssuming we have such entity: class Employee Long id Programmers can choose from high-level constructs requiring minimum amount of code or dive deep into nitty-gritty implementation details, while accepting a more verbose solution. It also gives a lot of flexibility in terms of available abstractions. Spring Data is a great way to simplify your code accessing the database. ![]()
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