Setting default values for columns in JPA

Question

Is it possible to set a default value for columns in JPA  and if  how is it done using annotations

User · Accepted Answer

Actually it is possible in JPA  although a little bit of a hack using the columnDefinition property of the  Column annotation  for example    Column name  Price   columnDefinition  Decimal 10 2  default  100 00

User · Answer

You can t do this with the column annotation  I think the only way is to set the default value when a object is created  Maybe the default constructor would be the right place to do that

User · Answer

This isn t possible in JPA   Here s what you can do with the Column annotation  http   java sun com javaee 5 docs api javax persistence Column html

User · Answer

In 2017  JPA 2 1 still has only  Column columnDefinition        to which you put the literal SQL definition of the column  Which is quite unflexible and forces you to also declare the other aspects like type  short-circuiting the JPA implementation s view on that matter   Hibernate though  has this    Column length   4096  nullable   false   org hibernate annotations ColumnDefault     private String description       Identifies the DEFAULT value to apply to the associated column via DDL     Hibernate 4 3 docs  4 3 to show it s been here for quite some time    Hibernate manual on Default value for database column   Two notes to that   1  Don t be afraid of going non-standard  Working as a JBoss developer  I ve seen quite some specification processes  The specification is basically the baseline that the big players in given field are willing to commit to support for the next decade or so  It s true for security  for messaging  ORM is no difference  although JPA covers quite a lot   My experience as a developer is that in a complex application  sooner or later you will need a non-standard API anyway  And  ColumnDefault is an example when it outweigts the negatives of using a non-standard solution   2  It s nice how everyone waves  PrePersist or constructor member initialization  But that s NOT the same  How about bulk SQL updates  How about statements that don t set the column  DEFAULT has it s role and that s not substitutable by initializing a Java class member

User · Answer

Column columnDefinition  tinyint 1  default 1     I just tested the issue  It works just fine  Thanks for the hint      About the comments    Column name  price    private double price   0 0    This one doesn t set the default column value in the database  of course

User · Answer

PrePersist void preInsert         if  this dateOfConsent    null          this dateOfConsent   LocalDateTime now        if this consentExpiry  null          this consentExpiry   this dateOfConsent plusMonths 3       In my case due to  the field being LocalDateTime i used this  it is recommended due to vendor independence

User · Answer

In my case  I modified hibernate-core source code  well  to introduce a new annotation  DefaultValue   commit 34199cba96b6b1dc42d0d19c066bd4d119b553d5 Author  Lenik  lt xjl at 99jsj com gt  Date    Wed Dec 21 13 28 33 2011  0800      Add default-value ddl support with annotation  DefaultValue   diff --git a hibernate-core src main java org hibernate annotations DefaultValue java b hibernate-core src main java org hibernate annotations DefaultValue java new file mode 100644 index 0000000  b3e605e ---  dev null     b hibernate-core src main java org hibernate annotations DefaultValue java    -0 0  1 35     package org hibernate annotations     import static java lang annotation ElementType FIELD   import static java lang annotation ElementType METHOD   import static java lang annotation RetentionPolicy RUNTIME     import java lang annotation Retention             Specify a default value for the column          This is used to generate the auto DDL          WARNING  This is not part of JPA 2 0 specification           author            java lang annotation Target   FIELD  METHOD      Retention RUNTIME   public  interface DefaultValue                      The default value sql fragment                  For string values  you need to quote the value like  foo                   Because different database implementation may use different          quoting format  so this is not portable  But for simple values         like number and strings  this is generally enough for use                String value         diff --git a hibernate-core src main java org hibernate cfg Ejb3Column java b hibernate-core src main java org hibernate cfg Ejb3Column java index b289b1e  ac57f1a 100644 --- a hibernate-core src main java org hibernate cfg Ejb3Column java     b hibernate-core src main java org hibernate cfg Ejb3Column java    -29 6  29 7    import org hibernate AnnotationException   import org hibernate AssertionFailure   import org hibernate annotations ColumnTransformer   import org hibernate annotations ColumnTransformers   import org hibernate annotations DefaultValue   import org hibernate annotations common reflection XProperty   import org hibernate cfg annotations Nullability   import org hibernate mapping Column     -65 6  66 7    public class Ejb3Column       private String propertyName      private boolean unique      private boolean nullable   true      private String defaultValue      private String formulaString      private Formula formula      private Table table     -175 7  177 15    public class Ejb3Column           return mappingColumn isNullable           -   public Ejb3Column         public String getDefaultValue              return defaultValue                public void setDefaultValue String defaultValue             this defaultValue   defaultValue                public Ejb3Column                public void bind        -186 7  196 7    public class Ejb3Column                     else               initMappingColumn  -                   logicalColumnName  propertyName  length  precision  scale  nullable  sqlType  unique  true                     logicalColumnName  propertyName  length  precision  scale  nullable  sqlType  unique  defaultValue  true                            log debug   Binding column      toString                  -201 6  211 7    public class Ejb3Column               boolean nullable              String sqlType              boolean unique              String defaultValue              boolean applyNamingStrategy            if   StringHelper isNotEmpty  formulaString                   this formula   new Formula       -217 6  228 7    public class Ejb3Column               this mappingColumn setNullable  nullable                this mappingColumn setSqlType  sqlType                this mappingColumn setUnique  unique                this mappingColumn setDefaultValue defaultValue                if writeExpression    null  amp  amp   writeExpression matches                                     throw new AnnotationException     -454 6  466 11    public class Ejb3Column                       else                           column setLogicalColumnName  columnName                                              DefaultValue  defaultValue   inferredData getProperty   getAnnotation DefaultValue class                       if   defaultValue    null                            String defaultValue    defaultValue value                            column setDefaultValue defaultValue                                              column setPropertyName                              BinderHelper getRelativePath  propertyHolder  inferredData getPropertyName     diff --git a hibernate-core src main java org hibernate cfg Ejb3JoinColumn java b hibernate-core src main java org hibernate cfg Ejb3JoinColumn java index e57636a  3d871f7 100644 --- a hibernate-core src main java org hibernate cfg Ejb3JoinColumn java     b hibernate-core src main java org hibernate cfg Ejb3JoinColumn java    -423 6  424 7    public class Ejb3JoinColumn extends Ejb3Column                   getMappingColumn      null   getMappingColumn   isNullable     false                  referencedColumn getSqlType                    getMappingColumn      null   getMappingColumn   isUnique     false                  null     default-value                 false                    linkWithValue  value       -502 6  504 7    public class Ejb3JoinColumn extends Ejb3Column                   getMappingColumn   isNullable                    column getSqlType                    getMappingColumn   isUnique                    null     default-value                 false   We do copy no strategy here                    linkWithValue  value      Well  this is a hibernate-only solution

User · Answer

If you re using a double  you can use the following    Column columnDefinition  double precision default  96     private Double grolsh    Yes it s db specific

User · Answer

JPA doesn t support that and it would be useful if it did  Using columnDefinition is DB-specific and not acceptable in many cases  setting a default in the class is not enough when you retrieve a record having null values  which typically happens when you re-run old DBUnit tests   What I do is this    public class MyObject       int attrib   0           Default is 0         Column   nullable   true       public int getAttrib            Falls to default   0 when null        public void setAttrib   Integer attrib            this attrib   attrib    null   0   attrib            Java auto-boxing helps a lot in that

User · Answer

This isn t possible in JPA   Here s what you can do with the Column annotation  http   java sun com javaee 5 docs api javax persistence Column html

User · Answer

You can t do this with the column annotation  I think the only way is to set the default value when a object is created  Maybe the default constructor would be the right place to do that

User · Answer

Column columnDefinition        doesn t work when you set the default constraint in database while inserting the data  You need to make insertable   false and remove columnDefinition       from annotation  then database will automatically insert the default value from the database  E g  when you set varchar gender is male by default in database  You just need to add insertable   false in Hibernate JPA  it will work

User · Answer

You can define the default value in the database designer  or when you create the table   For instance in SQL Server you can set the default vault of a Date field to  getDate      Use insertable false as mentioned in your column definition  JPA will not specify that column on inserts and the database will generate the value for you

User · Answer

You can do the following    Column name  price   private double price   0 0    There  You ve just used zero as the default value   Note this will serve you if you re only accessing the database from this application  If other applications also use the database  then you should make this check from the database using Cameron s columnDefinition annotation attribute  or some other way

User · Answer

Seeing as I stumbled upon this from Google while trying to solve the very same problem  I m just gonna throw in the solution I cooked up in case someone finds it useful   From my point of view there s really only 1 solutions to this problem --  PrePersist  If you do it in  PrePersist  you gotta check if the value s been set already though

User · Answer

Neither JPA nor Hibernate annotations support the notion of a default column value   As a workaround to this limitation  set all default values just before you invoke a Hibernate save   or update   on the session  This closely as possible  short of Hibernate setting the default values  mimics the behaviour of the database which sets default values when it saves a row in a table   Unlike setting the default values in the model class as this alternative answer suggests  this approach also ensures that criteria queries that use an Example object as a prototype for the search will continue to work as before   When you set the default value of a nullable attribute  one that has a non-primitive type  in a model class  a Hibernate query-by-example will no longer ignore the associated column where previously it would ignore it because it was null

User · Answer

This isn t possible in JPA   Here s what you can do with the Column annotation  http   java sun com javaee 5 docs api javax persistence Column html

User · Answer

In 2017  JPA 2 1 still has only  Column columnDefinition        to which you put the literal SQL definition of the column  Which is quite unflexible and forces you to also declare the other aspects like type  short-circuiting the JPA implementation s view on that matter   Hibernate though  has this    Column length   4096  nullable   false   org hibernate annotations ColumnDefault     private String description       Identifies the DEFAULT value to apply to the associated column via DDL     Hibernate 4 3 docs  4 3 to show it s been here for quite some time    Hibernate manual on Default value for database column   Two notes to that   1  Don t be afraid of going non-standard  Working as a JBoss developer  I ve seen quite some specification processes  The specification is basically the baseline that the big players in given field are willing to commit to support for the next decade or so  It s true for security  for messaging  ORM is no difference  although JPA covers quite a lot   My experience as a developer is that in a complex application  sooner or later you will need a non-standard API anyway  And  ColumnDefault is an example when it outweigts the negatives of using a non-standard solution   2  It s nice how everyone waves  PrePersist or constructor member initialization  But that s NOT the same  How about bulk SQL updates  How about statements that don t set the column  DEFAULT has it s role and that s not substitutable by initializing a Java class member

User · Answer

another approach is using javax persistence PrePersist   PrePersist void preInsert        if  this createdTime    null         this createdTime   new Date

User · Answer

This isn t possible in JPA   Here s what you can do with the Column annotation  http   java sun com javaee 5 docs api javax persistence Column html

User · Answer

You can t do this with the column annotation  I think the only way is to set the default value when a object is created  Maybe the default constructor would be the right place to do that

User · Answer

If you re using a double  you can use the following    Column columnDefinition  double precision default  96     private Double grolsh    Yes it s db specific

User · Answer

I use columnDefinition and it works very good   Column columnDefinition  TIMESTAMP DEFAULT CURRENT TIMESTAMP    private Date createdDate

User · Answer

PrePersist void preInsert         if  this dateOfConsent    null          this dateOfConsent   LocalDateTime now        if this consentExpiry  null          this consentExpiry   this dateOfConsent plusMonths 3       In my case due to  the field being LocalDateTime i used this  it is recommended due to vendor independence

User · Answer

you can use the java reflect api        PrePersist     void preInsert            PrePersistUtil pre this           This is common       public class PrePersistUtil            private static SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd              public static void pre Object object               try                   Field   fields   object getClass   getDeclaredFields                    for Field field   fields                       field setAccessible true                       if  field getType   getName   equals  java lang Long                                amp  amp  field get object     null                           field set object 0L                        else if     field getType   getName   equals  java lang String                                amp  amp  field get object     null                           field set object                           else if  field getType   getName   equals  java util Date                                amp  amp  field get object     null                           field set object sdf parse  1900-01-01                          else if  field getType   getName   equals  java lang Double                                amp  amp  field get object     null                           field set object 0 0d                        else if  field getType   getName   equals  java lang Integer                                amp  amp  field get object     null                           field set object 0                        else if  field getType   getName   equals  java lang Float                                amp  amp  field get object     null                           field set object 0 0f                                                         catch  IllegalAccessException e                    e printStackTrace                  catch  ParseException e                    e printStackTrace

User · Answer

You can t do this with the column annotation  I think the only way is to set the default value when a object is created  Maybe the default constructor would be the right place to do that

User · Answer

In my case  I modified hibernate-core source code  well  to introduce a new annotation  DefaultValue   commit 34199cba96b6b1dc42d0d19c066bd4d119b553d5 Author  Lenik  lt xjl at 99jsj com gt  Date    Wed Dec 21 13 28 33 2011  0800      Add default-value ddl support with annotation  DefaultValue   diff --git a hibernate-core src main java org hibernate annotations DefaultValue java b hibernate-core src main java org hibernate annotations DefaultValue java new file mode 100644 index 0000000  b3e605e ---  dev null     b hibernate-core src main java org hibernate annotations DefaultValue java    -0 0  1 35     package org hibernate annotations     import static java lang annotation ElementType FIELD   import static java lang annotation ElementType METHOD   import static java lang annotation RetentionPolicy RUNTIME     import java lang annotation Retention             Specify a default value for the column          This is used to generate the auto DDL          WARNING  This is not part of JPA 2 0 specification           author            java lang annotation Target   FIELD  METHOD      Retention RUNTIME   public  interface DefaultValue                      The default value sql fragment                  For string values  you need to quote the value like  foo                   Because different database implementation may use different          quoting format  so this is not portable  But for simple values         like number and strings  this is generally enough for use                String value         diff --git a hibernate-core src main java org hibernate cfg Ejb3Column java b hibernate-core src main java org hibernate cfg Ejb3Column java index b289b1e  ac57f1a 100644 --- a hibernate-core src main java org hibernate cfg Ejb3Column java     b hibernate-core src main java org hibernate cfg Ejb3Column java    -29 6  29 7    import org hibernate AnnotationException   import org hibernate AssertionFailure   import org hibernate annotations ColumnTransformer   import org hibernate annotations ColumnTransformers   import org hibernate annotations DefaultValue   import org hibernate annotations common reflection XProperty   import org hibernate cfg annotations Nullability   import org hibernate mapping Column     -65 6  66 7    public class Ejb3Column       private String propertyName      private boolean unique      private boolean nullable   true      private String defaultValue      private String formulaString      private Formula formula      private Table table     -175 7  177 15    public class Ejb3Column           return mappingColumn isNullable           -   public Ejb3Column         public String getDefaultValue              return defaultValue                public void setDefaultValue String defaultValue             this defaultValue   defaultValue                public Ejb3Column                public void bind        -186 7  196 7    public class Ejb3Column                     else               initMappingColumn  -                   logicalColumnName  propertyName  length  precision  scale  nullable  sqlType  unique  true                     logicalColumnName  propertyName  length  precision  scale  nullable  sqlType  unique  defaultValue  true                            log debug   Binding column      toString                  -201 6  211 7    public class Ejb3Column               boolean nullable              String sqlType              boolean unique              String defaultValue              boolean applyNamingStrategy            if   StringHelper isNotEmpty  formulaString                   this formula   new Formula       -217 6  228 7    public class Ejb3Column               this mappingColumn setNullable  nullable                this mappingColumn setSqlType  sqlType                this mappingColumn setUnique  unique                this mappingColumn setDefaultValue defaultValue                if writeExpression    null  amp  amp   writeExpression matches                                     throw new AnnotationException     -454 6  466 11    public class Ejb3Column                       else                           column setLogicalColumnName  columnName                                              DefaultValue  defaultValue   inferredData getProperty   getAnnotation DefaultValue class                       if   defaultValue    null                            String defaultValue    defaultValue value                            column setDefaultValue defaultValue                                              column setPropertyName                              BinderHelper getRelativePath  propertyHolder  inferredData getPropertyName     diff --git a hibernate-core src main java org hibernate cfg Ejb3JoinColumn java b hibernate-core src main java org hibernate cfg Ejb3JoinColumn java index e57636a  3d871f7 100644 --- a hibernate-core src main java org hibernate cfg Ejb3JoinColumn java     b hibernate-core src main java org hibernate cfg Ejb3JoinColumn java    -423 6  424 7    public class Ejb3JoinColumn extends Ejb3Column                   getMappingColumn      null   getMappingColumn   isNullable     false                  referencedColumn getSqlType                    getMappingColumn      null   getMappingColumn   isUnique     false                  null     default-value                 false                    linkWithValue  value       -502 6  504 7    public class Ejb3JoinColumn extends Ejb3Column                   getMappingColumn   isNullable                    column getSqlType                    getMappingColumn   isUnique                    null     default-value                 false   We do copy no strategy here                    linkWithValue  value      Well  this is a hibernate-only solution

User · Answer

JPA doesn t support that and it would be useful if it did  Using columnDefinition is DB-specific and not acceptable in many cases  setting a default in the class is not enough when you retrieve a record having null values  which typically happens when you re-run old DBUnit tests   What I do is this    public class MyObject       int attrib   0           Default is 0         Column   nullable   true       public int getAttrib            Falls to default   0 when null        public void setAttrib   Integer attrib            this attrib   attrib    null   0   attrib            Java auto-boxing helps a lot in that

User · Answer

Seeing as I stumbled upon this from Google while trying to solve the very same problem  I m just gonna throw in the solution I cooked up in case someone finds it useful   From my point of view there s really only 1 solutions to this problem --  PrePersist  If you do it in  PrePersist  you gotta check if the value s been set already though

User · Answer

Column columnDefinition        doesn t work when you set the default constraint in database while inserting the data  You need to make insertable   false and remove columnDefinition       from annotation  then database will automatically insert the default value from the database  E g  when you set varchar gender is male by default in database  You just need to add insertable   false in Hibernate JPA  it will work

User · Answer

Neither JPA nor Hibernate annotations support the notion of a default column value   As a workaround to this limitation  set all default values just before you invoke a Hibernate save   or update   on the session  This closely as possible  short of Hibernate setting the default values  mimics the behaviour of the database which sets default values when it saves a row in a table   Unlike setting the default values in the model class as this alternative answer suggests  this approach also ensures that criteria queries that use an Example object as a prototype for the search will continue to work as before   When you set the default value of a nullable attribute  one that has a non-primitive type  in a model class  a Hibernate query-by-example will no longer ignore the associated column where previously it would ignore it because it was null

User · Answer

You can do the following    Column name  price   private double price   0 0    There  You ve just used zero as the default value   Note this will serve you if you re only accessing the database from this application  If other applications also use the database  then you should make this check from the database using Cameron s columnDefinition annotation attribute  or some other way

User · Answer

I use columnDefinition and it works very good   Column columnDefinition  TIMESTAMP DEFAULT CURRENT TIMESTAMP    private Date createdDate

User · Answer

another approach is using javax persistence PrePersist   PrePersist void preInsert        if  this createdTime    null         this createdTime   new Date

User · Answer

You can define the default value in the database designer  or when you create the table   For instance in SQL Server you can set the default vault of a Date field to  getDate      Use insertable false as mentioned in your column definition  JPA will not specify that column on inserts and the database will generate the value for you

User · Answer

Column columnDefinition  tinyint 1  default 1     I just tested the issue  It works just fine  Thanks for the hint      About the comments    Column name  price    private double price   0 0    This one doesn t set the default column value in the database  of course

User · Answer

you can use the java reflect api        PrePersist     void preInsert            PrePersistUtil pre this           This is common       public class PrePersistUtil            private static SimpleDateFormat sdf   new SimpleDateFormat  yyyy-MM-dd              public static void pre Object object               try                   Field   fields   object getClass   getDeclaredFields                    for Field field   fields                       field setAccessible true                       if  field getType   getName   equals  java lang Long                                amp  amp  field get object     null                           field set object 0L                        else if     field getType   getName   equals  java lang String                                amp  amp  field get object     null                           field set object                           else if  field getType   getName   equals  java util Date                                amp  amp  field get object     null                           field set object sdf parse  1900-01-01                          else if  field getType   getName   equals  java lang Double                                amp  amp  field get object     null                           field set object 0 0d                        else if  field getType   getName   equals  java lang Integer                                amp  amp  field get object     null                           field set object 0                        else if  field getType   getName   equals  java lang Float                                amp  amp  field get object     null                           field set object 0 0f                                                         catch  IllegalAccessException e                    e printStackTrace                  catch  ParseException e                    e printStackTrace

[java] Setting default values for columns in JPA

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