[英]Hibernate not using defined sequence (postgresql)
I'm trying to insert mapped object to postgresql database with correct id. 我正在尝试将映射对象插入到具有正确ID的postgresql数据库。 This is how i insert: 这是我插入的方式:
Session session = Main.getSession();
Transaction rx = session.beginTransaction();
ProductsEntity productsEntity = new ProductsEntity();
productsEntity.setName(nameTextField.getText());
productsEntity.setDescription(descriptionTextArea.getText());
productsEntity.setCategory((ProductCategoriesEntity) categoryComboBox.getSelectedItem());
productsEntity.setPrice(new BigDecimal(1.0));
session.save(productsEntity);
tx.commit();
session.close();
Class with defined sequence: 具有已定义序列的类:
@Entity
@Table(name = "products", schema = "public", catalog = "shop")
public class ProductsEntity {
private int id;
private String name;
private String description;
private BigDecimal price;
@Id
@Column(name = "id", nullable = false)
@SequenceGenerator(name="pk_sequence",sequenceName="products_id_seq")
@GeneratedValue(strategy=GenerationType.AUTO,generator="pk_sequence")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Basic
@Column(name = "name", nullable = false, length = -1)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Basic
@Column(name = "description", nullable = false, length = -1)
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Basic
@Column(name = "price", nullable = false, precision = 2)
public BigDecimal getPrice() {
return price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ProductsEntity that = (ProductsEntity) o;
if (id != that.id) return false;
if (name != null ? !name.equals(that.name) : that.name != null) return false;
if (description != null ? !description.equals(that.description) : that.description != null) return false;
if (price != null ? !price.equals(that.price) : that.price != null) return false;
return true;
}
@Override
public int hashCode() {
int result = id;
result = 31 * result + (name != null ? name.hashCode() : 0);
result = 31 * result + (description != null ? description.hashCode() : 0);
result = 31 * result + (price != null ? price.hashCode() : 0);
return result;
}
private ProductCategoriesEntity category;
@ManyToOne
public ProductCategoriesEntity getCategory() {
return category;
}
public void setCategory(ProductCategoriesEntity category) {
this.category = category;
}
}
Last value of postgresql sequence products_id_seq is 4. Hibernate is inserting object with id=0, so first insert was successful, now I'm getting unique constraint violation. postgresql序列products_id_seq的最后一个值是4.Hibernate插入id = 0的对象,所以第一次插入成功,现在我遇到了唯一的约束违规。
EDIT I've made sequence work by adding generator 编辑我通过添加生成器使序列工作
<generator class="identity"/>
in xml mapping definition 在xml映射定义中
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="entities.ProductsEntity" table="products" schema="public" catalog="shop">
<id name="id">
<column name="id" sql-type="integer"/>
<generator class="identity"/>
</id>
<property name="name">
<column name="name" sql-type="varchar"/>
</property>
<property name="description">
<column name="description" sql-type="varchar"/>
</property>
<property name="price">
<column name="price" sql-type="numeric(9,2)" precision="9" scale="2"/>
</property>
<many-to-one name="category" column="category_id" class="entities.ProductCategoriesEntity" lazy="false"/>
</class>
</hibernate-mapping>
This works without defining sequence in class. 这无需在课堂上定义序列。 I've also tried to use 我也试过用
@GeneratedValue(strategy=GenerationType.IDENTITY)
in class file but it doesn't work. 在类文件中,但它不起作用。
If someone has an idea please tell me why only "xml" method works. 如果有人有想法,请告诉我为什么只有“xml”方法有效。
Is the sequence "products_id_seq" a DB Sequence? 序列“products_id_seq”是DB序列吗?
If Yes, then change your GenerationType
from Auto
to SEQUENCE
. 如果是,则将GenerationType
从Auto
更改为SEQUENCE
。
I've a similar setup with Postgres and setting GenerationType as SEQUENCE and giving allocationSize = 1 worked for me. 我和Postgres有类似的设置,并将GenerationType设置为SEQUENCE ,并为我提供了allocationSize = 1 。
Also, ensure your sequence is upto date with the table. 此外,请确保您的序列与表格保持同步。 If not, Alter the sequence for now so your further updates will not fail. 如果没有,请立即更改序列,以便进一步更新不会失败。
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