Hibernate Column
This tutorial explains the concept of column annotation in hibernate.
Hibernate column :
In Hibernate, column attribute plays an important role in mapping table. column annotation is defined in javax.persistence package. It is used to define a mapped column for a persistence field.
As we map table fields in our persistence class by using @column annotation and also we can specify other properties.
Syntax -
@Column(name="column_name" ,columnDefinition="CLOB NOT NULL" ,insertable=true/false ,length=N ,nullable=true/false ,precision=N ,scale=N ,table="" ,unique=true/false ,updatable=true/false)
Description of Optional Elements:
name: It is name of column that represent to table field. by
default it takes field name or property.
Default value: ""
columnDefinition: It shows the SQL fragment that is used
when generating the DDL for the column. By default it takes the generated SQL to
create a column of the inferred type.
Default value: ""
insertable: It is used to check for the column is included
in SQL INSERT statements which is generated by the persistence provider or not.
Default value: true
nullable: It is of Boolean type and checks the column name
is either nullable or not.
Default value: true
length: It is optional and sets the column length only if you
use string valued column.
Default value : 255
precision: It is optional applies only if a decimal column
is used. Value is set by programmer if used when generating the DDL for column.
Default value: 0
scale: It is used for scaling for a decimal(exact numeric)
column and is applied only if a decimal column is presented.
Default value : 0
table: It refer to the name of the table that contains the
column. If it is not present then the column name is assumed to be in the
primary table.
Default value: ""
unique: It checks whether the property is a unique key or
not. It is useful for checking unique key constraint of single field.
Default value: false
updatable: It checks whether the column updatable or not
Default value: true