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Posted to ojb-user@db.apache.org by ZZZ Liu <z2...@yahoo.com> on 2004/01/28 05:05:08 UTC
How to set null for a column for which the corresponding java type is long
Hi, All
I have a data base column. The data type is number
(10). It is nullable. The JDBC type defined in
repository is BIGINT and the corresponding java type
is long (default). Can anybody tell me how to save a
record so that the value of that column is null
instead of zero?
Thanks,
Zhe
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Re: How to set null for a column for which the corresponding java
type is long
Posted by Martin Kalén <ma...@curalia.se>.
Danilo Tommasina wrote:
>> I have a data base column. The data type is number
>> (10). It is nullable. The JDBC type defined in
>> repository is BIGINT and the corresponding java type
>> is long (default). Can anybody tell me how to save a
>> record so that the value of that column is null
>> instead of zero?
>
> Do not use a primitive data type in your persistent class, use instead a
> subtype of Number. (Integer, Long, BigInteger, BigDecimal,... )
Or; if you don't have control over the bean or want to keep long, use a
field conversion class that converts long values of 0 as NULL.
There are quite a few pre-packaged field conversion classes that come
with OJB, they can be found in the package:
org.apache.ojb.broker.accesslayer.conversions
The Int2IntegerFieldConversion class can be used as a template for how
to write a field conversion for a long with 0-inserts as NULL.
See
http://cvs.apache.org/viewcvs.cgi/*checkout*/db-ojb/src/java/org/apache/ojb/broker/accesslayer/conversions/Int2IntegerFieldConversion.java?content-type=text%2Fplain&rev=1.3
To use field conversions, specify them in your repository. Eg:
<class-descriptor class="{x}" table="{x}">
<field-descriptor name="{x}" column="{x}" jdbc-type="{x}"
conversion="com.mycompany.PrimitiveLong2LongFieldConversion"/>
HTH,
Martin
--
Martin Kalén
Curalia AB Web: http://www.curalia.se
Orrspelsvägen 2B Mail: info@curalia.se
SE-182 79 Stocksund Tel: +46-8-410 064 40
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Re: Joins
Posted by Armin Waibel <ar...@code-au-lait.de>.
Hi Ankur,
Ankur Gupta wrote:
> I am trying to run a direct SQL query using OJB and not sure how to make
> it work. The query I am trying to run is a join of 2 classes. I haven't
> specified any join mappings in the repository file. Want to do this
> manually. Can you please provide me an example on how to do this
> specific thing?
Hope this will help you
http://db.apache.org/ojb/faq.html#Is it possible to perform my own
sql-queries in OJB?
regards,
Armin
>
>
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Joins
Posted by Ankur Gupta <an...@coreconcept.com>.
I am trying to run a direct SQL query using OJB and not sure how to make
it work. The query I am trying to run is a join of 2 classes. I haven't
specified any join mappings in the repository file. Want to do this
manually. Can you please provide me an example on how to do this
specific thing?
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Re: How to set null for a column for which the corresponding java
type is long
Posted by Andrei Ivanov <an...@ines.ro>.
But isn't that much slower?
/me is a newbie in java and ojb
On Wed, 28 Jan 2004, Danilo Tommasina wrote:
> Hi,
>
> Do not use a primitive data type in your persistent class, use instead a
> subtype of Number. (Integer, Long, BigInteger, BigDecimal,... )
>
>
> cheers
> Danilo
>
> > Hi, All
> >
> > I have a data base column. The data type is number
> > (10). It is nullable. The JDBC type defined in
> > repository is BIGINT and the corresponding java type
> > is long (default). Can anybody tell me how to save a
> > record so that the value of that column is null
> > instead of zero?
> >
> > Thanks,
> > Zhe
> >
> > __________________________________
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> > Yahoo! SiteBuilder - Free web site building tool. Try it!
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> >
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> >
>
>
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Re: How to set null for a column for which the corresponding java
type is long
Posted by Danilo Tommasina <dt...@risksys.com>.
Hi,
Do not use a primitive data type in your persistent class, use instead a
subtype of Number. (Integer, Long, BigInteger, BigDecimal,... )
cheers
Danilo
> Hi, All
>
> I have a data base column. The data type is number
> (10). It is nullable. The JDBC type defined in
> repository is BIGINT and the corresponding java type
> is long (default). Can anybody tell me how to save a
> record so that the value of that column is null
> instead of zero?
>
> Thanks,
> Zhe
>
> __________________________________
> Do you Yahoo!?
> Yahoo! SiteBuilder - Free web site building tool. Try it!
> http://webhosting.yahoo.com/ps/sb/
>
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