Java数据库错误（抽象模式类型未知）

Question

I got this error message when I try to create my login menu, before that there is not problem. Don't know since when this problem occur and there is no error notice.

[EL Info]: 2018-08-15 19:16:20.494--ServerSession(15826265)--EclipseLink, version: Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd
[EL Info]: connection: 2018-08-15 19:16:20.624--ServerSession(15826265)--file:/C:/Users/Tan Jun Wen/Documents/NetBeansProjects/JavaProgramming2_Assignment/build/classes/_Investment company databasePU logout successful
[EL Severe]: ejb: 2018-08-15 19:16:20.627--ServerSession(15826265)--Exception [EclipseLink-0] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Problem compiling [SELECT a FROM Admin_1 a WHERE a.adminRegisterDate = :adminRegisterDate]. 
[14, 21] The abstract schema type 'Admin_1' is unknown.
[30, 49] The state field path 'a.adminRegisterDate' cannot be resolved to a valid type.

Answer 1

If your class like this:

@Entity
@Table(name = "Admin_1")
public class Admin {

@Column(name = "ADMIN_REGISTER_DATE")
private Date adminRegisterDate;
......
}

And you working with object fields (a.adminRegisterDate) in JPQL, you need use classname "Admin" and not "Admin_1" in query.

SELECT a FROM Admin a WHERE a.adminRegisterDate = :adminRegisterDate