Postgres DDL 错误：''user' 处或附近的语法错误'

Question

我正在尝试使用 postgres 数据库设置 Spring Boot 项目。我的实体是：-

用户

@Entity
public class User implements UserDetails {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="id", nullable = false, updatable = false)
    private Long id;
    private String username;
    private String password;
    private String firstName;
    private String lastName;

    @Column(name="email", nullable = false, updatable = false)
    private String email;
    private String phone;
    private boolean enabled=true;


    @OneToMany(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    @JsonIgnore
    private Set<UserRole> userRoles = new HashSet<>();

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }

    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }
    public Set<UserRole> getUserRoles() {
        return userRoles;
    }
    public void setUserRoles(Set<UserRole> userRoles) {
        this.userRoles = userRoles;
    }
    @Override
    public Collection<? extends GrantedAuthority> getAuthorities() {
        Set<GrantedAuthority> authorites = new HashSet<>();
        userRoles.forEach(ur -> authorites.add(new Authority(ur.getRole().getName())));

        return authorites;
    }
    @Override
    public boolean isAccountNonExpired() {
        // TODO Auto-generated method stub
        return true;
    }
    @Override
    public boolean isAccountNonLocked() {
        // TODO Auto-generated method stub
        return true;
    }
    @Override
    public boolean isCredentialsNonExpired() {
        // TODO Auto-generated method stub
        return true;
    }

    @Override
    public boolean isEnabled() {
        return enabled;
    }

}

角色

@Entity
public class Role {

    @Id
    private int roleId;
    private String name;

    @OneToMany(mappedBy = "role", cascade=CascadeType.ALL, fetch=FetchType.LAZY)
    private Set<UserRole> userRoles = new HashSet<>();

    public int getRoleId() {
        return roleId;
    }

    public void setRoleId(int roleId) {
        this.roleId = roleId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Set<UserRole> getUserRoles() {
        return userRoles;
    }

    public void setUserRoles(Set<UserRole> userRoles) {
        this.userRoles = userRoles;
    }


}

USER_ROLE

@Entity
@Table(name="user_role")
public class UserRole {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long userRoleId;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name="user_id")
    private User user;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name="role_id")
    private Role role;

    public UserRole(){}

    public UserRole(User user, Role role) {
        this.user = user;
        this.role = role;
    }


    public Long getUserRoleId() {
        return userRoleId;
    }


    public void setUserRoleId(Long userRoleId) {
        this.userRoleId = userRoleId;
    }


    public User getUser() {
        return user;
    }


    public void setUser(User user) {
        this.user = user;
    }


    public Role getRole() {
        return role;
    }


    public void setRole(Role role) {
        this.role = role;
    }


}

我的application.properties文件看起来像：-

server.port=5060    
spring.thymeleaf.cache=false

spring.datasource.url=jdbc:postgresql://localhost:5432/pcms
spring.datasource.data-username=sagar
spring.datasource.password=sagar

spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQL94Dialect
spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults = false

所以每当我运行这个应用程序时。在 postgresql 数据库上成功创建了 user_role 和 role 表。但用户实体抛出异常。

错误说：-

2018-05-07 15:44:15.847  WARN 23619 --- [  restartedMain] o.h.t.s.i.ExceptionHandlerLoggedImpl     : GenerationTarget encountered exception accepting command : Error executing DDL via JDBC Statement

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlString(SchemaCreatorImpl.java:440) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlStrings(SchemaCreatorImpl.java:424) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.createFromMetadata(SchemaCreatorImpl.java:375) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.performCreation(SchemaCreatorImpl.java:166) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:135) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:121) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:155) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:312) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:460) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:892) [hibernate-core-5.2.16.Final.jar:5.2.16.Final]

at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.0.1.RELEASE.jar:2.0.1.RELEASE]
Caused by: org.postgresql.util.PSQLException: ERROR: syntax error at or near "user"
  Position: 108

正如您可以看到USER实体上的错误点。但是当应用程序连接到 mysql 数据库时，同一个实体运行良好。我无法弄清楚它背后的真正错误是什么。

Answer 1

User实际上是一个保留关键字，Spring JPA 不会按原样“转义”。但是，您可以在实体声明中像这样执行关键字转义：

@Entity
@Table(name = "\"User\"")
public class User implements UserDetails { ... }

Spring 可能会在您的 MySql 数据库中为您转义它或以其他方式为您处理它；您的 PostgreSQL 数据库并非如此。