第九章：Entity + Repository —— 档案馆怎么记卷宗

package com.example.cityhall.permit;

import jakarta.persistence.*;

@Entity
@Table(name = "permit_applications")
public class PermitApplication {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  @Column(nullable = false, length = 100)
  private String citizenName;

  @Column(nullable = false, length = 50)
  private String permitType;
}

package com.example.cityhall.permit;

import org.springframework.data.jpa.repository.JpaRepository;

public interface PermitRepository extends JpaRepository<PermitApplication, Long> {
  boolean existsByCitizenNameAndPermitType(String citizenName, String permitType);
}