休眠和Oracle序列

问题描述

我有一个Oracle序列和Hibernate的问题。我使用这段代码来获取带有hibernate的Oracle序列

  
您应该将 allocationSize 设置为 1  
 $ $ p $ code $ @ student_id_seq，
 sequenceName =Student_seq，
 allocationSize = 1）
  

您可以阅读文档

I have a problem with Oracle sequence and Hibernate. I used this code to get Oracle Sequence with hibernate

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "student_id_seq")
@SequenceGenerator(name = "student_id_seq", sequenceName = "Student_seq")
@Column(name = "StudentID")
public Long getStudentId() {
    return this.studentId;
}

public void setStudentId(Long studentId) {
    this.studentId = studentId;
}

but when i insert a new value to the table, the generated value is incorrect. For example:when I had two records in database with id 2 and 3, and when I inserted new one, it's id was not 4 but 25. I have no idea what to do with it.

解决方案

You should set allocationSize to 1

@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "student_id_seq")
@SequenceGenerator(name = "student_id_seq", 
                   sequenceName = "Student_seq",
                   allocationSize = 1)  

You can read more in documentation SequenceGenerator doc

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