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Hibernate Column

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This tutorial explains the concept of column annotation in hibernate.

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

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Posted on: July 4, 2012

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