Question

我不明白为什么在我的应用程序中插入新用户时， usr 表的主键总是递增2而不是1。我正在使用Oracle11g数据库。如果我手动插入 usr 表，一切正常。

此外， usr 表和角色表具有 usr_role 连接表，其中包含组合主键。 JPA将 usr 的正确主键插入到连接表中。只有在 usr 表中，它才会增加2。

我用来创建用户架构的SQL：

function ConvertFrom-Xml {
<#
.SYNOPSIS
    Converts XML object to PSObject representation for further ConvertTo-Json transformation
.EXAMPLE
    # JSON->XML
    $xml = ConvertTo-Xml (get-content 1.json | ConvertFrom-Json) -Depth 4 -NoTypeInformation -as String
.EXAMPLE
    # XML->JSON
    ConvertFrom-Xml ([xml]($xml)).Objects.Object | ConvertTo-Json
#>
    param([System.Xml.XmlElement]$Object)

    if (($Object -ne $null) -and ($Object.Property -ne $null)) {
        $PSObject = New-Object PSObject

        foreach ($Property in @($Object.Property)) {
            if ($Property.Property.Name -like 'Property') {
                $PSObject | Add-Member NoteProperty $Property.Name ($Property.Property | % {ConvertFrom-Xml $_})
            } else {
                if ($Property.'#text' -ne $null) {
                    $PSObject | Add-Member NoteProperty $Property.Name $Property.'#text'
                } else {
                    if ($Property.Name -ne $null) {
                        $PSObject | Add-Member NoteProperty $Property.Name (ConvertFrom-Xml $Property)
                    }
                }
            } 
        }   
        $PSObject
    }
}

用户实体：

CREATE TABLE usr (
id NUMBER(19) PRIMARY KEY,
email VARCHAR2(40) NOT NULL UNIQUE,
password VARCHAR2(10) NOT NULL CHECK(LENGTH(password) >= 6),
username VARCHAR2(15) NOT NULL UNIQUE
);
GRANT SELECT, INSERT, UPDATE, DELETE ON usr TO forum_user;

DROP SEQUENCE seq_usr;
CREATE SEQUENCE seq_usr;
GRANT ALL ON seq_usr TO forum_user;

CREATE OR REPLACE TRIGGER tri_usr
BEFORE INSERT ON usr
FOR EACH ROW
BEGIN :NEW.id := seq_usr.NEXTVAL;
END;
/

这是JPA SQL输出：

@Entity
@Table(schema = "FORUM", name = "USR")
public class User implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(
            name = "USR_ID_GENERATOR",
            sequenceName = "SEQ_USR",
            schema = "FORUM",
            allocationSize = 1,
            initialValue = 1
    )
    @GeneratedValue(
            strategy = GenerationType.SEQUENCE,
            generator = "USR_ID_GENERATOR"
    )
    private Long id;

    @NotNull
    @Size(min = 3, max = 40)
    @Pattern(regexp = "[a-zA-Z0-9]+@[a-zA-Z0-9]+\\.[a-zA-Z0-9]+", message = "has to be valid")
    private String email;

    @NotNull
    @Size(min = 6, max = 10)
    private String password;

    @NotNull
    @Size(min = 4, max = 20)
    private String username;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(name = "USR_ROLE",
            joinColumns = @JoinColumn(name = "USR_ID", referencedColumnName = "ID"),
            inverseJoinColumns = @JoinColumn(name = "ROLE_ID", referencedColumnName = "ID")
    )
    private List<Role> roles;

    public User() {}

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public List<Role> getRoles() {
        return roles;
    }

    public void setRoles(List<Role> roles) {
        this.roles = roles;
    }

    public boolean addRole(Role role) {
        if (roles == null) {
            roles = new ArrayList<>();
        }
        return roles.add(role);
    }
}

Answer 1

尝试连接到数据库并要求nextval在那里隔离问题是在Oracle中还是在JPA配置中有些疯狂的事情。

Answer 2

我建议使用如下序列：

而不是使用触发器。我相信触发器只会在数据更新后执行，一旦有更新就会导致另一次更新。

JPA表主键增加2而不是1

2 个答案: