NamedQueries使用什么类型的查询？

Question

我正在使用netbean的选项从数据库创建实体类，我不习惯这个“方言”查询，我想了解更多关于它的语法。有人能告诉我这个查询的“方言”或语法的名称是什么？

@NamedQueries({
@NamedQuery(name = "Users.findAll", query = "SELECT u FROM Users u")
, @NamedQuery(name = "Users.findByUserId", query = "SELECT u FROM Users u WHERE u.userId = :userId")
, @NamedQuery(name = "Users.findByName", query = "SELECT u FROM Users u WHERE u.name= :name")
, @NamedQuery(name = "Users.findBySurname", query = "SELECT u FROM Users u WHERE u.surname= :surname")
, @NamedQuery(name = "Users.findByEmail", query = "SELECT u FROM Users u WHERE u.email = :email")
, @NamedQuery(name = "Users.findByDateOfBirth", query = "SELECT u FROM Users u WHERE u.dateob= :dateob")
, @NamedQuery(name = "Users.findByPassword", query = "SELECT u FROM Users u WHERE u.password= :password")})

Answer 1

它不是SQL，它是JPQL（Java持久性查询语言），它是在JPA（Java Persistence API）规范中定义的。

JPA的实现（例如Hibernate）将使用正确的SQL方言将其转换为SQL查询，以获取他们正在访问的数据源。