带有命名参数的本机查询失败，并显示“未设置所有命名参数"； [英] Native query with named parameter fails with "Not all named parameters have been set"

问题描述

我想执行一个简单的原生查询，但它不起作用:

I want to execute a simple native query, but it does not work:

@Autowired
private EntityManager em;

Query q = em.createNativeQuery("SELECT count(*) FROM mytable where username = :username");
em.setProperty("username", "test");
(int) q.getSingleResult();

为什么我会收到此异常?

Why am I getting this exception?

org.hibernate.QueryException: Not all named parameters have been set: [username]

推荐答案

JPA 在原生查询中不支持命名参数，仅适用于 JPQL.您必须使用位置参数.

Named parameters are not supported by JPA in native queries, only for JPQL. You must use positional parameters.

命名参数遵循第 4.4.1 节中定义的标识符规则.命名参数的使用适用于 Java Persistence 查询语言，并没有为本地查询定义.只有位置参数绑定可以移植地用于原生查询.

Named parameters follow the rules for identifiers defined in Section 4.4.1. The use of named parameters applies to the Java Persistence query language, and is not defined for native queries. Only positional parameter binding may be portably used for native queries.

所以，使用这个

Query q = em.createNativeQuery("SELECT count(*) FROM mytable where username = ?1");
q.setParameter(1, "test");

虽然 JPA 规范不支持原生查询中的命名参数，但一些 JPA 实现(如 Hibernate) 可能支持它

While JPA specification doesn't support named parameters in native queries, some JPA implementations (like Hibernate) may support it

本机 SQL 查询支持位置参数和命名参数

Native SQL queries support positional as well as named parameters

然而，这会将您的应用程序与特定的 JPA 实现结合起来，从而使其不可移植.

However, this couples your application to specific JPA implementation, and thus makes it unportable.

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