I've got the following class mapping a MySQL table:
#Entity
#Table(name = "category")
public class Category {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name = "id")
private long id;
#Column(name = "parent_id")
private long parentId;
and I get the following error when dealing with columns that have NULL value of parent_id column:
INFO: HHH000327: Error performing load command : org.hibernate.PropertyAccessException: Null value was assigned to a property of primitive type setter of com.blogspot.symfonyworld.wealthylaughingduck.model.Category.parentId
This is just a java error: NULL can't be assigned to long type (private long parentId). I couldn't find any hint how to overcome this problem and I can only think of replacing long with Long. Is it a good idea or maybe there is some built-in hibernate annotation or whatever mechanism to do this particular stuff?
You defined your class attribute as a primitive (long), but your database table contains null values for the corresponding column. The provider (Hibernate) does not map null's to primitive because the mapping is ambiguous.
In cases where your data may contain nulls you need to use the wrapper class equivalent (in this case, Long).
#Entity
#Table(name = "category")
public class Category {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name = "id")
private long id;
#Column(name = "parent_id")
private Long parentId;
}
If parentId is nullable and you need to map it as a field, you'll need to use the wrapper class.
But if (as I suspect from the filed name) you're mapping foreign keys explicitly as fields, you're likely missing out on some of an ORM's real strength in mapping associations.
I am using Spring 3 and Hibernate 4
I have the following in Entity class
#Id
#Column(name = "PROJECT_NO")
private String projectNumber;
When I insert values into database table, is it possible to insert PROJECT_NO value which is the Primary key in the following format
20131 where 2013 is the current year and next character should be incremental by one. i.e. next value to be inserted should be 20132
How can I achieve this using JPA/Hibernate
You have to look at #GeneratedValue and #GenericGenerator annotation.
There are several possibilities to generate value. In your case I believe the you need to create something like the following:
#Id
#GeneratedValue(strategy = GenerationType.AUTO, generator = "year_gen")
#GenericGenerator(name = "year_gen", strategy = "com.example.generator.CustomGenerator")
#Column(name = "PROJECT_NO")
private String projectNumber;
And CustomGenerator should implement org.hibernate.id.IdentifierGenerator
What about putting the JPA annotation on the getter and using the getter method to format the data as you like?
#Entity
public class MyClass {
private String projectNumber;
#Column(name = "PROJECT_NO")
public String getProjectNumber(){
return doSomeFormatting(this.projectNumber);
}
}
Something like that should work.
I have a post class and it kind of works, but there's one problem: the primary key doesn't increase.
#Entity
#Table(name="posts")
public class Post extends GenericModel{
#Id
#Column(name="post_id")
public int id;
#Column(name="post_situation")
public String situation;
#Column(name="post_date")
public Date date;
#Column(name="post_userid")
public int userid;
#OneToMany(mappedBy="post", cascade=CascadeType.ALL)
public List<Block> blocks;
public Post addBlock(String content, int position){
Block b = new Block(this, content, position);
b.save();
this.blocks.add(b);
this.save();
return this;
}
public Post(String situation, Date date){
this.situation = situation;
this.date = date;
this.userid = 2;
}
}
When I call it the first time on an empty table, it works fine, but the second time, I'm getting PersistenceException occured : org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
The post_id column always has 0. Any idea how to fix this? I have the #Id annotation in palce..
This is how I have in my controller:
Post p = new Post("Midden in het middenoosten.", new Date()).save();
Any ideas what's causing this problem?
It seems that you want the primary key values to be auto-generated. If that is the case, if you'll need to add the #GeneratedValue annotation to the id attribute, in addition to the #Id annotation. Your code should therefore be:
#Id
#Column(name="post_id")
#GeneratedValue
public int id;
There are several strategies available to generate the Ids. You would have to read up on those to decide if you want to choose the TABLE -based, SEQUENCE -based or the IDENTITY -based strategy (which depends on what your database supports). If you choose a strategy explicitly, the define strategy will be used, instead of the default AUTO strategy. Explicit strategy decisions, are communicated in code as:
#Id
#Column(name="post_id")
#GeneratedValue(strategy=SEQUENCE, generator="POST_SEQ")
public int id;
Without generated values, the default value for integers in Java, i.e. 0 will be persisted for the post_id column. Due to the primary key constraint, you cannot have a second row with the same key, resulting in the described failure.
There are several strategies available to generate id:
GenerationType.AUTO
GenerationType.SEQUENCE
GenerationType.IDENTITY
GenerationType.TABLE
If you want the primary key values to be auto-generated, use GenerationType.AUTO, it works with MySQL.
I have a domain object and annotated as follows
#Entity
#Table(name = "REQUEST")
public class Request {
/**
* Unique id for this request
*/
#Id
#GeneratedValue
#Column(name = "EQ_ID")
private long requestId;
/**
*
*/
#Column(name = "EMAIL_ID")
private String emailId;
/**
*
*/
#Column(name = "REQUEST_DATE")
private Date requestDate;
/**
*Getters/setters omitted
*/
}
The column Request_date cannot be null and as per the DDL the default value is sysdate (oracle DB). How do I annotate this field so that if the requestDate property is null,hiberanate automatically inserts sysdate.? Currently it throws error when the field is null,which is very obvious as it cannot be null as per the DB constraints. How do I go about this?
One alternative is to mark this field as transient and the inserts work fine. But the negative aspect is that, I will not be able to retrieve the value (of request_date column).
This is a missing feature in hibernate annotations. Also there exist some workaround as Yok has posted. The problem is that the workaround is vendor dependent and might not work for all DB. In my case,Oracle, it isn't working and has been reported as a bug.
You can put the default value in a columnDefinition. An example would look like:
#Column(name = "REQUEST_DATE", nullable = false, columnDefinition = "date default sysdate")
Using #ColumnDefault (Work for DDL update).
hibernate.hbm2ddl.auto=update
import org.hibernate.annotations.ColumnDefault;
....
#ColumnDefault(value="'#'")
#Column(name = "TEMP_COLUMN", nullable = false)
public String getTempColumn() {
return tempColumn;
}
DDL Generate:
Alter Table YOUR_TABLE add TEMP_COLUMN varchar2(255) default '#' not null;
Assign a default value to the field:
private Date requestDate = new Date();
If you mark your entity with #DynamicInsert e.g.
#Entity
#DynamicInsert
#Table(name = "TABLE_NAME")
public class ClassName implements Serializable {
Hibernate will generate SQL without null values. Then the database will insert its own default value. This does have performance implications See Dynamic Insert.
Make the default in Oracle for the column SYSDATE:
ALTER TABLE APP MODIFY (REQUEST_DATE DEFAULT SYSDATE);
Then, from Hibernate's perspective it can be nullable.
Hibernate will save a NULL to the database. Oracle will convert that to SYSDATE. And everyone will be happy.
I resolved assigning a value to the variable like this private Integer active= 0;
#Entity
#Table(name="products")
public class ServiziTipologia {
#Id
#GeneratedValue
private Integer id;
private String product;
private String description;
private Integer active= 0;
How do I set a default value in Hibernate field?
If you want a real database default value, use columnDefinition:
#Column(name = "myColumn", nullable = false, columnDefinition = "int default 100")
Notice that the string in columnDefinition is database dependent. Also if you choose this option, you have to use dynamic-insert, so Hibernate doesn't include columns with null values on insert. Otherwise talking about default is irrelevant.
But if you don't want database default value, but simply a default value in your Java code, just initialize your variable like that - private Integer myColumn = 100;
Use hibernate annotation.
#ColumnDefault("-1")
private Long clientId;
Recreate the table if it already exists for the changes to take effect.
You can use #PrePersist anotation and set the default value in pre-persist stage.
Something like that:
//... some code
private String myProperty;
//... some code
#PrePersist
public void prePersist() {
if(myProperty == null) //We set default value in case if the value is not set yet.
myProperty = "Default value";
}
// property methods
#Column(nullable = false) //restricting Null value on database level.
public String getMyProperty() {
return myProperty;
}
public void setMyProperty(String myProperty) {
this.myProperty= myProperty;
}
This method is not depend on database type/version underneath the Hibernate. Default value is set before persisting the mapping object.
what about just setting a default value for the field?
private String _foo = "default";
//property here
public String Foo
if they pass a value, then it will be overwritten, otherwise, you have a default.
Default entity property value
If you want to set a default entity property value, then you can initialize the entity field using the default value.
For instance, you can set the default createdOn entity attribute to the current time, like this:
#Column(
name = "created_on"
)
private LocalDateTime createdOn = LocalDateTime.now();
Default column value using JPA
If you are generating the DDL schema with JPA and Hibernate, although this is not recommended, you can use the columnDefinition attribute of the JPA #Column annotation, like this:
#Column(
name = "created_on",
columnDefinition = "DATETIME(6) DEFAULT CURRENT_TIMESTAMP"
)
#Generated(GenerationTime.INSERT)
private LocalDateTime createdOn;
The #Generated annotation is needed because we want to instruct Hibernate to reload the entity after the Persistence Context is flushed, otherwise, the database-generated value will not be synchronized with the in-memory entity state.
Instead of using the columnDefinition, you are better off using a tool like Flyway and use DDL incremental migration scripts. That way, you will set the DEFAULT SQL clause in a script, rather than in a JPA annotation.
Default column value using Hibernate
If you are using JPA with Hibernate, then you can also use the #ColumnDefault annotation, like this:
#Column(name = "created_on")
#ColumnDefault(value="CURRENT_TIMESTAMP")
#Generated(GenerationTime.INSERT)
private LocalDateTime createdOn;
Default Date/Time column value using Hibernate
If you are using JPA with Hibernate and want to set the creation timestamp, then you can use the #CreationTimestamp annotation, like this:
#Column(name = "created_on")
#CreationTimestamp
private LocalDateTime createdOn;
If you want to do it in database:
Set the default value in database (sql server sample):
ALTER TABLE [TABLE_NAME] ADD CONSTRAINT [CONSTRAINT_NAME] DEFAULT (newid()) FOR [COLUMN_NAME]
Mapping hibernate file:
<hibernate-mapping ....
...
<property name="fieldName" column="columnName" type="Guid" access="field" not-null="false" insert="false" update="false" />
...
See, the key is insert="false" update="false"
One solution is to have your getter check to see if whatever value you are working with is null (or whatever its non-initialized state would be) and if it's equal to that, just return your default value:
public String getStringValue(){
return (this.stringValue == null) ? "Default" : stringValue;
}
Use #ColumnDefault() annotation. This is hibernate only though.
I searched for this and found many answers to default value for column.If you want to use default value defined in SQL Table then in #Column Annotation use "insertable = false". insertable
#Column(name = columnName, length = lengthOfColumn, insertable = false)
If you are using columnDefination it #Column annotation may be it won't work as it is Database dependent.
Working with Oracle, I was trying to insert a default value for an Enum
I found the following to work the best.
#Column(nullable = false)
#Enumerated(EnumType.STRING)
private EnumType myProperty = EnumType.DEFAULT_VALUE;
To use default value from any column of table. then you must need to define #DynamicInsert as true or else you just define #DynamicInsert. Because hibernate takes by default as a true.
Consider as the given example:
#AllArgsConstructor
#Table(name = "core_contact")
#DynamicInsert
public class Contact implements Serializable {
#Column(name = "status", columnDefinition = "int default 100")
private Long status;
}
You can use the java class constructor to set the default values. For example:
public class Entity implements Serializable{
private Double field1
private Integer field2;
private T fieldN;
public Entity(){
this.field1=0.0;
this.field2=0;
...
this.fieldN= <your default value>
}
//Setters and Getters
...
}
I tried it. when i did that
#Column(name = "is_sale", columnDefinition = "default false")
private boolean isSale = false;
he did not add. And when I did
#Column(name = "is_sale", columnDefinition = "bool default false")
private boolean isSale = false;
in this case Hibernate generated such sql
alter table if exists customer_product add column is_sale bool default false
and it helped me
<property name="age" type="integer">
<column name="age" not-null="false" default="null" />
</property>
i'am working with hibernate 5 and postgres, and this worked form me.
#Column(name = "ACCOUNT_TYPE", ***nullable***=false, columnDefinition="varchar2 default 'END_USER'")
#Enumerated(EnumType.STRING)
private AccountType accountType;
If you want to set default value in terms of database, just set #Column( columnDefinition = "int default 1")
But if what you intend is to set a default value in your java app you can set it on your class attribute like this: private Integer attribute = 1;
Suppose we have an entity which contains a sub-entity.
Using insertable = false, updatable = false on the entity prevents the entity from creating new sub-entities and preceding the default DBMS value. But the problem with this is that we are obliged to always use the default value or if we need the entity to contain another sub-entity that is not the default, we must try to change these annotations at runtime to insertable = true, updatable = true, so it doesn't seem like a good path.
Inside the sub-entity if it makes more sense to use in all the columns insertable = false, updatable = false so that no more sub-entities are created regardless of the method we use (with #DynamicInsert it would not be necessary)
Inserting a default value can be done in various ways such as Default entity property value using constructor or setter. Other ways like using JPA with columnDefinition have the drawback that they insert a null by default and the default value of the DBMS does not precede.
Insert default value using DBMS and optional using Hibernate
But using #DynamicInsert we avoid sending a null to the db when we want to insert a sub-entity with its default value, and in turn we allow sub-entities with values other than the default to be inserted.
For inserting, should this entity use dynamic sql generation where only non-null columns get referenced in the prepared sql statement?
Given the following needs:
The entity does not have the responsibility of creating new sub-entities.
When inserting an entity, the sub-entity is the one that was defined as default in the DBMS.
Possibility of creating an entity with a sub-entity which has a UUID other than the default.
DBMS: PostgreSQL | Language: Kotlin
#Entity
#Table(name = "entity")
#DynamicInsert
data class EntityTest(
#Id #GeneratedValue #Column(name = "entity_uuid") val entityUUID: UUID? = null,
#OneToOne(cascade = [CascadeType.ALL])
#JoinColumn(name = "subentity_uuid", referencedColumnName = "subentity_uuid")
var subentityTest: SubentityTest? = null
) {}
#Entity
#Table(name = "subentity")
data class SubentityTest(
#Id #GeneratedValue #Column(name = "subentity_uuid", insertable = false, updatable = false) var subentityUUID: UUID? = null,
#Column(insertable = false, updatable = false) var name: String,
) {
constructor() : this(name = "")
}
And the value is set by default in the database:
alter table entity alter column subentity_uuid set default 'd87ee95b-06f1-52ab-83ed-5d882ae400e6'::uuid;
GL
Source 1
Source 2
we can have getter that annotates #Column
all #column should be annotated in getter alone instead of direct variable declaration. by this way, we can resolve it.
#Column(name = "string_value")
public String getStringValue(){
return (this.stringValue == null) ? "Default" : stringValue;
}