blocks|key|346594|text|看看GeneratedValue的策略。它通常看起来像这样：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|346595|@GeneratedValue(strategy=GenerationType.IDENTITY)|code-block|syntax|javascript|346596|entityMap^0|2|E|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Take a look at <code>GeneratedValue</code>'s strategy. It typically looks something like:

<pre><code>@GeneratedValue(strategy=GenerationType.IDENTITY)
</code></pre>

blocks|key|346610|text|有时，即使在执行了SchemaUpdate之后，对模型或对象关系映射所做的更改也不能准确地反映在数据库上。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|346611|如果错误实际上似乎缺乏合理的解释，请尝试重新创建数据库(或至少创建一个新数据库)，并使用SchemaExport搭建它。|346612|entityMap^0|9|C|0|18|C|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

Sometimes changes made to the model or to the ORM may not reflect accurately on the database even after an execution of <code>SchemaUpdate</code>.

If the error actually seems to lack a sensible explanation, try recreating the database (or at least creating a new one) and scaffolding it with <code>SchemaExport</code>.

blocks|key|3328838|text|将方法hashCode()添加到实体Bean类中，然后重试|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3328839|entityMap^0|3|A|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Add a method <code>hashCode()</code> to your Entity Bean Class and retry it

blocks|key|343269|text|请检查列id的默认值，特别是table.if是否没有设为默认值|type|unstyled|depth|inlineStyleRanges|entityRanges|data|343270|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Please check whether the Default value for the column id in particular table.if not make it as default

blocks|key|344140|text|如果您希望MySQL自动生成主键，那么您必须在创建表时告知它。您不必在Oracle中执行此操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344141|在主键上，您必须包含AUTO_INCREMENT。请参见下面的示例。|offset|length|style|CODE|344142|CREATE+TABLE+`supplier`++
(++
++`ID`+int(11)+NOT+NULL+**AUTO_INCREMENT**,++
++`FIRSTNAME`+varchar(60)+NOT+NULL,++
++`SECONDNAME`+varchar(100)+NOT+NULL,++
++`PROPERTYNUM`+varchar(50)+DEFAULT+NULL,++
++`STREETNAME`+varchar(50)+DEFAULT+NULL,++
++`CITY`+varchar(50)+DEFAULT+NULL,++
++`COUNTY`+varchar(50)+DEFAULT+NULL,++
++`COUNTRY`+varchar(50)+DEFAULT+NULL,++
++`POSTCODE`+varchar(50)+DEFAULT+NULL,++
++`HomePHONENUM`+bigint(20)+DEFAULT+NULL,++
++`WorkPHONENUM`+bigint(20)+DEFAULT+NULL,++
++`MobilePHONENUM`+bigint(20)+DEFAULT+NULL,++
++`EMAIL`+varchar(100)+DEFAULT+NULL,++
++PRIMARY+KEY+(`ID`)++
)+

ENGINE=InnoDB+DEFAULT+CHARSET=latin1;++|code-block|syntax|javascript|344143|下面是实体|344144|package+com.keyes.jpa;++

import+java.io.Serializable;
import+javax.persistence.*;
import+java.math.BigInteger;

/**
+*+The+persistent+class+for+the+parkingsupplier+database+table.
+*+
+*/
@Entity
@Table(name+=+"supplier")
public+class+supplier+implements+Serializable
{
++private+static+final+long+serialVersionUID+=+1L;

++@Id
++**@GeneratedValue(strategy+=+GenerationType.IDENTITY)**
++@Column(name+=+"ID")
++private+long+id;

++@Column(name+=+"CITY")
++private+String+city;

++@Column(name+=+"COUNTRY")
++private+String+country;

++@Column(name+=+"COUNTY")
++private+String+county;

++@Column(name+=+"EMAIL")
++private+String+email;

++@Column(name+=+"FIRSTNAME")
++private+String+firstname;

++@Column(name+=+"HomePHONENUM")
++private+BigInteger+homePHONENUM;

++@Column(name+=+"MobilePHONENUM")
++private+BigInteger+mobilePHONENUM;

++@Column(name+=+"POSTCODE")
++private+String+postcode;

++@Column(name+=+"PROPERTYNUM")
++private+String+propertynum;

++@Column(name+=+"SECONDNAME")
++private+String+secondname;

++@Column(name+=+"STREETNAME")
++private+String+streetname;

++@Column(name+=+"WorkPHONENUM")
++private+BigInteger+workPHONENUM;

++public+supplier()
++{
++}

++public+long+getId()
++{
++++return+this.id;
++}

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

++public+String+getCity()
++{
++++return+this.city;
++}

++public+void+setCity(String+city)
++{
++++this.city+=+city;
++}

++public+String+getCountry()
++{
++++return+this.country;
++}

++public+void+setCountry(String+country)
++{
++++this.country+=+country;
++}

++public+String+getCounty()
++{
++++return+this.county;
++}

++public+void+setCounty(String+county)
++{
++++this.county+=+county;
++}

++public+String+getEmail()
++{
++++return+this.email;
++}

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

++public+String+getFirstname()
++{
++++return+this.firstname;
++}

++public+void+setFirstname(String+firstname)
++{
++++this.firstname+=+firstname;
++}

++public+BigInteger+getHomePHONENUM()
++{
++++return+this.homePHONENUM;
++}

++public+void+setHomePHONENUM(BigInteger+homePHONENUM)
++{
++++this.homePHONENUM+=+homePHONENUM;
++}

++public+BigInteger+getMobilePHONENUM()
++{
++++return+this.mobilePHONENUM;
++}

++public+void+setMobilePHONENUM(BigInteger+mobilePHONENUM)
++{
++++this.mobilePHONENUM+=+mobilePHONENUM;
++}

++public+String+getPostcode()
++{
++++return+this.postcode;
++}

++public+void+setPostcode(String+postcode)
++{
++++this.postcode+=+postcode;
++}

++public+String+getPropertynum()
++{
++++return+this.propertynum;
++}

++public+void+setPropertynum(String+propertynum)
++{
++++this.propertynum+=+propertynum;
++}

++public+String+getSecondname()
++{
++++return+this.secondname;
++}

++public+void+setSecondname(String+secondname)
++{
++++this.secondname+=+secondname;
++}

++public+String+getStreetname()
++{
++++return+this.streetname;
++}

++public+void+setStreetname(String+streetname)
++{
++++this.streetname+=+streetname;
++}

++public+BigInteger+getWorkPHONENUM()
++{
++++return+this.workPHONENUM;
++}

++public+void+setWorkPHONENUM(BigInteger+workPHONENUM)
++{
++++this.workPHONENUM+=+workPHONENUM;
++}

}|344145|entityMap^0|0|A|E|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|W|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|Y|8|@]|9|@]|A|$K|L]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

If you want MySQL to automatically produce primary keys then you have to tell it when creating the table. You don't have to do this in Oracle.

On the Primary Key you have to include <code>AUTO_INCREMENT</code>. See the example below.

<pre><code>CREATE TABLE `supplier` 
( 
 `ID` int(11) NOT NULL **AUTO_INCREMENT**, 
 `FIRSTNAME` varchar(60) NOT NULL, 
 `SECONDNAME` varchar(100) NOT NULL, 
 `PROPERTYNUM` varchar(50) DEFAULT NULL, 
 `STREETNAME` varchar(50) DEFAULT NULL, 
 `CITY` varchar(50) DEFAULT NULL, 
 `COUNTY` varchar(50) DEFAULT NULL, 
 `COUNTRY` varchar(50) DEFAULT NULL, 
 `POSTCODE` varchar(50) DEFAULT NULL, 
 `HomePHONENUM` bigint(20) DEFAULT NULL, 
 `WorkPHONENUM` bigint(20) DEFAULT NULL, 
 `MobilePHONENUM` bigint(20) DEFAULT NULL, 
 `EMAIL` varchar(100) DEFAULT NULL, 
 PRIMARY KEY (`ID`) 
) 

ENGINE=InnoDB DEFAULT CHARSET=latin1; 
</code></pre>

Here's the Entity

<pre><code>package com.keyes.jpa; 

import java.io.Serializable;
import javax.persistence.*;
import java.math.BigInteger;

/**
 * The persistent class for the parkingsupplier database table.
 * 
 */
@Entity
@Table(name = "supplier")
public class supplier implements Serializable
{
 private static final long serialVersionUID = 1L;

 @Id
 **@GeneratedValue(strategy = GenerationType.IDENTITY)**
 @Column(name = "ID")
 private long id;

 @Column(name = "CITY")
 private String city;

 @Column(name = "COUNTRY")
 private String country;

 @Column(name = "COUNTY")
 private String county;

 @Column(name = "EMAIL")
 private String email;

 @Column(name = "FIRSTNAME")
 private String firstname;

 @Column(name = "HomePHONENUM")
 private BigInteger homePHONENUM;

 @Column(name = "MobilePHONENUM")
 private BigInteger mobilePHONENUM;

 @Column(name = "POSTCODE")
 private String postcode;

 @Column(name = "PROPERTYNUM")
 private String propertynum;

 @Column(name = "SECONDNAME")
 private String secondname;

 @Column(name = "STREETNAME")
 private String streetname;

 @Column(name = "WorkPHONENUM")
 private BigInteger workPHONENUM;

 public supplier()
 {
 }

 public long getId()
 {
 return this.id;
 }

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

 public String getCity()
 {
 return this.city;
 }

 public void setCity(String city)
 {
 this.city = city;
 }

 public String getCountry()
 {
 return this.country;
 }

 public void setCountry(String country)
 {
 this.country = country;
 }

 public String getCounty()
 {
 return this.county;
 }

 public void setCounty(String county)
 {
 this.county = county;
 }

 public String getEmail()
 {
 return this.email;
 }

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

 public String getFirstname()
 {
 return this.firstname;
 }

 public void setFirstname(String firstname)
 {
 this.firstname = firstname;
 }

 public BigInteger getHomePHONENUM()
 {
 return this.homePHONENUM;
 }

 public void setHomePHONENUM(BigInteger homePHONENUM)
 {
 this.homePHONENUM = homePHONENUM;
 }

 public BigInteger getMobilePHONENUM()
 {
 return this.mobilePHONENUM;
 }

 public void setMobilePHONENUM(BigInteger mobilePHONENUM)
 {
 this.mobilePHONENUM = mobilePHONENUM;
 }

 public String getPostcode()
 {
 return this.postcode;
 }

 public void setPostcode(String postcode)
 {
 this.postcode = postcode;
 }

 public String getPropertynum()
 {
 return this.propertynum;
 }

 public void setPropertynum(String propertynum)
 {
 this.propertynum = propertynum;
 }

 public String getSecondname()
 {
 return this.secondname;
 }

 public void setSecondname(String secondname)
 {
 this.secondname = secondname;
 }

 public String getStreetname()
 {
 return this.streetname;
 }

 public void setStreetname(String streetname)
 {
 this.streetname = streetname;
 }

 public BigInteger getWorkPHONENUM()
 {
 return this.workPHONENUM;
 }

 public void setWorkPHONENUM(BigInteger workPHONENUM)
 {
 this.workPHONENUM = workPHONENUM;
 }

}
</code></pre>

blocks|key|346667|text|我也有同样的问题。我使用的是一个连接表，我所拥有的只有一个行id字段和两个外键。我不知道确切的原因，但我做了以下操作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|346668|346669|将MySQL升级到社区5.5.13|ordered-list-item|346670|重命名类和表|346671|确保我有哈希码和equals方法|346672|346673|@Entity+@表(名称=+"USERGROUP")公共类UserGroupBean实现可序列化{私有静态最终长serialVersionUID+=+1L；@Id+@GeneratedValue(strategy=GenerationType.AUTO)+@Column(名称=+"USERGROUP_ID")私有长列；@Column(名称=+"USER_ID")私有长列；@Column(名称=+"GROUP_ID")私有长group_id;|346674|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|P|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|Q|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|R|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|S|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

I had the same problem. I was using a join table and all I had with a row id field and two foreign keys. I don't know the exact caused but I did the following

<ol>
<li>Upgraded MySQL to community 5.5.13</li>
<li>Rename the class and table</li>
<li>Make sure I had hashcode and equals methods

<pre><code>@Entity 
@Table(name = "USERGROUP")
public class UserGroupBean implements Serializable {
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name = "USERGROUP_ID")
private Long usergroup_id;

@Column(name = "USER_ID") 
private Long user_id;

@Column(name = "GROUP_ID")
private Long group_id;
</code></pre></li>
</ol>

blocks|key|346682|text|另一个建议是检查自动生成的字段是否使用了有效的类型。请记住，它不适用于String，但适用于Long：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|346683|@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public+Long+id;

@Constraints.Required
public+String+contents;|code-block|syntax|javascript|346684|上面的语法适用于使用Hibernate作为JPA2.0提供程序在MySQL中生成表。|346685|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Another suggestion is to check that you use a valid type for the auto-generated field. Remember that it doesn't work with String, but it works with Long:

<pre><code>@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public Long id;

@Constraints.Required
public String contents;
</code></pre>

The above syntax worked for generating tables in MySQL using Hibernate as a JPA 2.0 provider.

blocks|key|343356|text|必须在hbm2ddl属性中使用update。进行更改并将其更新为Create，以便它可以创建表。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|343357|<property+name="hbm2ddl.auto">create</property>|code-block|syntax|javascript|343358|这对我很管用。|343359|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

you must be using update in your hbm2ddl property. make the changes and update it to Create so that it can create the table.

<pre><code>&lt;property name="hbm2ddl.auto"&gt;create&lt;/property&gt;
</code></pre>

It worked for me.

blocks|key|343361|text|我来这里是因为这个错误消息，原来我有两个同名的表。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|343362|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I came here because of the error message, turns out I had two tables with the same name.

blocks|key|3328964|text|仅添加非空约束|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3328965|我也有同样的问题。我刚刚在xml映射中添加了非空约束。It+worked|3328966|<set+name="phone"+cascade="all"+lazy="false"+>+
+++<key+column="id"+not-null="true"+/>
+++<one-to-many+class="com.practice.phone"/>
</set>|code-block|syntax|javascript|3328967|entityMap^0|0|7|0|R|9|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

Just add not-null constraint 

I had the same problem. I just added not-null constraint in xml mapping. It worked

<pre><code>&lt;set name="phone" cascade="all" lazy="false" &gt; 
 &lt;key column="id" not-null="true" /&gt;
 &lt;one-to-many class="com.practice.phone"/&gt;
&lt;/set&gt;
</code></pre>

blocks|key|3328990|text|我也有同样的问题。我找到了教程Hibernate+One-To-One+Mapping+Example+using+Foreign+key+Annotation并一步一步地遵循它，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3328991|使用以下脚本创建数据库表：|3328992|create+table+ADDRESS+(
+++id+INT(11)+NOT+NULL+AUTO_INCREMENT,
+++street+VARCHAR(250)+NOT+NULL,
+++city++VARCHAR(100)+NOT+NULL,
+++country++VARCHAR(100)+NOT+NULL,
+++PRIMARY+KEY+(id)
);

create+table+STUDENT+(
++++id++++++++++++INT(11)+NOT+NULL+AUTO_INCREMENT,+
++++name++++++++++VARCHAR(100)+NOT+NULL,+
++++entering_date+DATE+NOT+NULL,+
++++nationality+++TEXT+NOT+NULL,+
++++code++++++++++VARCHAR(30)+NOT+NULL,
++++address_id+INT(11)+NOT+NULL,
++++PRIMARY+KEY+(id),
++++CONSTRAINT+student_address+FOREIGN+KEY+(address_id)+REFERENCES+ADDRESS+(id)+++
);|code-block|syntax|javascript|3328993|以下是具有上表的实体|3328994|@Entity
@Table(name+=+"STUDENT")
public+class+Student+implements+Serializable+{

++++private+static+final+long+serialVersionUID+=+6832006422622219737L;

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

+}

@Entity
@Table(name+=+"ADDRESS")
public+class+Address+{

++++@Id+@GeneratedValue
++++@Column(name+=+"ID")
++++private+long+id;
}|3328995|问题已解决。|3328996|注意:主键必须设置为AUTO_INCREMENT|3328997|entityMap|0|LINK|mutability|MUTABLE|url|http://javabycode.com/java-frameworks/hibernate-4-tutorial/hibernate-one-to-one-mapping-example-using-foreign-key-annotation.html^0|F|1T|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|6|7|14|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|15|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|16|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|17|8|@]|9|@]|C|$I|J]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|C|$]]|$1|Q|3|R|5|6|7|19|8|@]|9|@]|C|$]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]]|T|$U|$5|V|W|X|C|$Y|Z]]]]

I had the same problem. I found the tutorial <a href="http://javabycode.com/java-frameworks/hibernate-4-tutorial/hibernate-one-to-one-mapping-example-using-foreign-key-annotation.html" rel="nofollow">Hibernate One-To-One Mapping Example using Foreign key Annotation</a> and followed it step by step like below:

Create database table with this script:

<pre><code>create table ADDRESS (
 id INT(11) NOT NULL AUTO_INCREMENT,
 street VARCHAR(250) NOT NULL,
 city VARCHAR(100) NOT NULL,
 country VARCHAR(100) NOT NULL,
 PRIMARY KEY (id)
);

create table STUDENT (
 id INT(11) NOT NULL AUTO_INCREMENT, 
 name VARCHAR(100) NOT NULL, 
 entering_date DATE NOT NULL, 
 nationality TEXT NOT NULL, 
 code VARCHAR(30) NOT NULL,
 address_id INT(11) NOT NULL,
 PRIMARY KEY (id),
 CONSTRAINT student_address FOREIGN KEY (address_id) REFERENCES ADDRESS (id) 
);
</code></pre>

Here is the entities with the above tables

<pre><code>@Entity
@Table(name = "STUDENT")
public class Student implements Serializable {

 private static final long serialVersionUID = 6832006422622219737L;

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

 }

@Entity
@Table(name = "ADDRESS")
public class Address {

 @Id @GeneratedValue
 @Column(name = "ID")
 private long id;
}
</code></pre>

The problem was resolved. 

Notice: The primary key must be set to AUTO_INCREMENT

blocks|key|346772|text|如果DB表有一个旧的未删除的列，则会抛出相同的异常。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|346773|例如：attribute_id+NOT+NULL+BIGINT(20),和attributeId+NOT+NULL+BIGINT(20),|offset|length|style|CODE|346774|删除not+used属性后，在我的例子中是contractId，问题就解决了。|BOLD|346775|entityMap^0|0|3|X|11|W|0|L|A|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@$D|O|E|P|F|G]|$D|Q|E|R|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|S|8|@$D|T|E|U|F|J]]|9|@]|A|$]]|$1|K|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|L|$]]

The same exception was thrown if a DB table had an old unremoved column.

For example:
<code>attribute_id NOT NULL BIGINT(20),</code> and <code>attributeId NOT NULL BIGINT(20),</code>

After removing the not used attribute, in my case contractId, the problem was resolved.

blocks|key|3116350|text|我遇到了这个问题，因为我错误地将@Transient注释放在了该特定属性的上方。在我的例子中，这个错误是有意义的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3116351|entityMap^0|G|A|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

I had this issue, by mistake I had placed <code>@Transient</code> annotation above that particular attribute. In my case this error make sense.

blocks|key|3329066|text|这发生在我和@ManyToMany的关系上。我已经注释了与@JoinTable关系中的一个字段，我删除了它，并在@ManyToMany上使用了mappedBy属性。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3329067|entityMap^0|6|B|T|A|1Z|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|O|8|@]|D|@]|E|$]]]|G|$]]

This happened to me with a <code>@ManyToMany</code> relationship. I had annotated one of the fields in the relationship with <code>@JoinTable</code>, I removed that and used the <code>mappedBy</code> attribute on @ManyToMany instead.

blocks|key|344269|text|手动从数据库中删除表，然后重新运行应用程序对我很有效。在我的案例中，我猜表没有正确创建(带有约束)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344270|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Dropping the table from the database manually and then re-running the application worked for me. In my case table was not created properly(with constraints) I guess.

blocks|key|344272|text|除了上面提到的，在创建sql表以使自动递增时不要忘记，如本例所示。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|344273|CREATE+TABLE+MY_SQL_TABLE+(

++USER_ID+INTEGER+NOT+NULL+AUTO_INCREMENT+PRIMARY+KEY,
++FNAME+VARCHAR(50)+NOT+NULL,
++LNAME+VARCHAR(20)+NOT+NULL,
++EMAIL+VARCHAR(50)+NOT+NULL
);|code-block|syntax|javascript|344274|entityMap^0|8|I|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

In addition to what is mentioned above, do not forget while creating sql table to make the AUTO INCREMENT as in this example

<pre><code>CREATE TABLE MY_SQL_TABLE (

 USER_ID INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY,
 FNAME VARCHAR(50) NOT NULL,
 LNAME VARCHAR(20) NOT NULL,
 EMAIL VARCHAR(50) NOT NULL
);
</code></pre>

blocks|key|344285|text|我尝试了这个代码，在我的例子中，下面的代码解决了这个问题。我还没有正确地确定模式|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344286|@Entity
++++@Table(name="table"
+++++++++,catalog="databasename"
++++++)|code-block|syntax|javascript|344287|请尝试像我一样添加,catalog="databasename"。|offset|length|style|CODE|344288|,catalog="databasename"|344289|entityMap^0|0|0|9|N|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I tried the code and in my case the code below solve the issue. I had not settled the schema properly 

<pre><code>@Entity
 @Table(name="table"
 ,catalog="databasename"
 )
</code></pre>

Please try to add <code>,catalog="databasename"</code> the same as I did. 

<pre><code>,catalog="databasename"
</code></pre>

blocks|key|341968|text|在我的例子中，我修改了有问题的表和字段"id“，我将其设为AUTO_INCREMENT，我仍然需要弄清楚为什么在部署时它没有设为"AUTO_INCREMENT”，所以我必须自己来做！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|341969|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

In my case, 
I altered that offending tables and the field "id" in question I made it AUTO_INCREMENT, I still need to figure out why on deployment time it was not making it "AUTO_INCREMENT" so that I have to do it by myself!

blocks|key|3116432|text|这样如何：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3116433|<set+name="fieldName"+cascade="all">+
+++<key+column="id"+not-null="true"+/>
+++<one-to-many+class="com.yourClass"/>
</set>|code-block|syntax|javascript|3116434|我希望它能对你有所帮助。|3116435|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

What about this:

<pre><code>&lt;set name="fieldName" cascade="all"&gt; 
 &lt;key column="id" not-null="true" /&gt;
 &lt;one-to-many class="com.yourClass"/&gt;
&lt;/set&gt;
</code></pre>

I hope it helps you.

blocks|key|344308|text|也许这就是表模式的问题所在。删除表并重新运行应用程序。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|344309|entityMap^0|E|3|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Maybe that is the problem with the table schema. drop the table and rerun the application.

blocks|key|3329206|text|尝试将Long对象类型更改为long原语类型(如果您可以使用原语类型)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3329207|我也有同样的问题，改变类型对我很有帮助。|3329208|entityMap^0|3|4|E|4|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

Try to change <code>Long</code> object type to <code>long</code> primitive type (if using primitives is ok for you). 

I had the same problem and changing type helped me.

blocks|key|341994|text|我有这个问题。我的错误是我将可插入和可更新的字段设置为false，并试图在请求中设置该字段。此字段在DB中设置为非NULL。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|341995|@ManyToOne
@JoinColumn(name="roles_id",++referencedColumnName+=+"id",+insertable+=+false,+updatable+=+false,+nullable=false)
@JsonBackReference
private+Role+role;|code-block|syntax|javascript|341996|后来我将其更改为-+insertable+=+true，updatable+=+true|341997|@ManyToOne
@JoinColumn(name="roles_id",++referencedColumnName+=+"id",+insertable+=+true,+updatable+=+true,+nullable=false)
@JsonBackReference
//@JsonIgnore
private+Role+role;|341998|后来它完美地发挥了作用。|341999|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I had this issue. My mistake was i had set the insertable and updatable fileds as false and was trying to set the field in the request. This field is set as NON NULL in DB.

<pre><code>@ManyToOne
@JoinColumn(name="roles_id", referencedColumnName = "id", insertable = false, updatable = false, nullable=false)
@JsonBackReference
private Role role;
</code></pre>

Later I changed it to - insertable = true, updatable = true 

<pre><code>@ManyToOne
@JoinColumn(name="roles_id", referencedColumnName = "id", insertable = true, updatable = true, nullable=false)
@JsonBackReference
//@JsonIgnore
private Role role;
</code></pre>

It worked perfectly later.

blocks|key|343516|text|“字段'id‘没有默认值”，因为您没有在GeneratedValue注释中声明GenerationType.IDENTITY。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|343517|@Id
@GeneratedValue(strategy+=+GenerationType.IDENTITY)
private+int+id;|code-block|syntax|javascript|343518|entityMap^0|K|E|13|N|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

"Field 'id' doesn't have a default value" because you didn't declare <code>GenerationType.IDENTITY</code> in <code>GeneratedValue</code> Annotation.

<pre><code>@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
</code></pre>

blocks|key|3329355|text|这个问题是因为有时你需要再次更新/创建数据库，或者有时如果你在db表中添加了字段，但没有实体类，那么它就不能插入任何空值或零，所以出现了这个错误。因此请同时检查side.Db和实体类。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3329356|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

This issue is because sometimes you need to again update/create the database or sometimes if you have added the field in db table but not not entity class then it can not insert any null value or zero so this error came. 
So check both side.Db and Entity class.

blocks|key|344382|text|当您的字段不可为空时，需要在创建表时指定默认值。使用正确初始化的AUTO_INCREMENT重新创建一个表，这样DB将不需要缺省值，因为它将自己生成缺省值，并且永远不会将NULL放在那里。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344383|CREATE+TABLE+Persons+(
Personid+int+NOT+NULL+AUTO_INCREMENT,
LastName+varchar(255)+NOT+NULL,
FirstName+varchar(255),
Age+int,
PRIMARY+KEY+(Personid)|code-block|syntax|javascript|344384|)；|344385|https://www.w3schools.com/sql/sql_autoincrement.asp|offset|length|344386|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|0|1F|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|U|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|V|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|W|8|@]|9|@$K|X|L|Y|1|Z]]|A|$]]|$1|M|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|J]]]]

When your field is not nullable it requires a default value to be specified on table creation. Recreate a table with AUTO_INCREMENT properly initialized so DB will not require default value since it will generate it by itself and never put NULL there.

<pre><code>CREATE TABLE Persons (
Personid int NOT NULL AUTO_INCREMENT,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
PRIMARY KEY (Personid)
</code></pre>

);

<a href="https://www.w3schools.com/sql/sql_autoincrement.asp" rel="nofollow noreferrer">https://www.w3schools.com/sql/sql_autoincrement.asp</a>

blocks|key|3116680|text|当模型字段与数据库中正确的表字段不匹配时，我在GCP云sql中得到了这样的错误。示例:+in+model字段为fieldName时|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3116681|db中的表应该有字段field_name帮助我修复表字段名。|3116682|entityMap^0|1J|9|0|A|A|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

i have got such error in GCP cloud sql when model field didn't match correct table field in db.
Example:
when in model field is <code>fieldName</code> 
table in db should have field <code>field_name</code>
Fixing table field name helped me.

blocks|key|3116722|text|我用@GeneratedValue(策略=+GenerationType.IDENTITY)通过@GeneratedValue(策略=+GenerationType.AUTO)解决了这个问题|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3116723|顺便说一句，我不需要把它放在创建中，只需：|3116724|spring.jpa.hibernate.ddl-auto:+update|code-block|syntax|javascript|3116725|entityMap^0|2|18|1C|14|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

I solved it changuing @GeneratedValue(strategy = GenerationType.IDENTITY) by @GeneratedValue(strategy = GenerationType.AUTO)
By the way i didn't need to put it to create, just:
<pre><code>spring.jpa.hibernate.ddl-auto: update
</code></pre>

blocks|key|344426|text|我解决了类似的问题，当我改变数据库列类型时，没有添加auto_increment。在alter+table命令中添加回auto_increment之后(就像我最初创建表时一样)，它可以工作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|344427|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I solved similar problem, when I altered the database column type , and did not add auto_increment. After adding back auto_increment in the alter table command (as in my original table creation) it worked

I'm facing what I think is a simple problem with Hibernate, but can't solve it (Hibernate forums being unreachable certainly doesn't help).

I have a simple class I'd like to persist, but keep getting:

<pre><code>SEVERE: Field 'id' doesn't have a default value
Exception in thread "main" org.hibernate.exception.GenericJDBCException: could not insert: [hibtest.model.Mensagem]
 at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
 at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
 [ a bunch more ]
Caused by: java.sql.SQLException: Field 'id' doesn't have a default value
 [ a bunch more ]
</code></pre>

The relevant code for the persisted class is:

<pre><code>package hibtest.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Mensagem {
 protected Long id;

 protected Mensagem() { }

 @Id
 @GeneratedValue
 public Long getId() {
 return id;
}

 public Mensagem setId(Long id) {
 this.id = id;
 return this;
 }
}
</code></pre>

And the actual running code is just plain:

<pre><code>SessionFactory factory = new AnnotationConfiguration()
 .configure()
 .buildSessionFactory();

{
 Session session = factory.openSession();
 Transaction tx = session.beginTransaction();

 Mensagem msg = new Mensagem("YARR!");

 session.save(msg);

 tx.commit();
 session.close();
}
</code></pre>

I tried some "strategies" within the <code>GeneratedValue</code> annotation but it just doesn't seem to work. Initializing <code>id</code> doesn't help either! (eg <code>Long id = 20L</code>).

Could anyone shed some light?

EDIT 2: confirmed: messing with<code>@GeneratedValue(strategy = GenerationType.XXX)</code> doesn't solve it

SOLVED: recreating the database solved the problem

Hibernate: "Field 'id' doesn't have a default value"

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正面临着一个我认为是Hibernate的简单问题，但不能解决它(Hibernate论坛是无法访问的，当然也无济于事)。我有一个简单的类，我想要持久化，但不断得到：SEVERE: Field 'id' doesn't have a default valueException in thread "main" org....

问Hibernate：“字段'id‘没有默认值”
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问Hibernate：“字段'id‘没有默认值”
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