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Storing empty strings in an oracle database [message #538322]

Mon, 07 June 2010 11:22

Alex

Messages: 2
Registered: June 2010

Junior Member

Hi,

I've a question how to handle empty strings and NULL for "String" columns in a oracle database.

I know Oracle treats an empty string as NULL and therefore a column definition with nullable=false will cause a rollback on inserts with an empty string as value.

The only workaround I've found is to use a "special character" to mark an empty string.

I want to support more than one database system, not only oracle.
I use EclipseLink 1.1.3

Are there any other solutions?

thanks!

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Re: Storing empty strings in an oracle database [message #538413 is a reply to message #538322]

Mon, 07 June 2010 15:31

Chris Delahunt

Messages: 1249
Registered: July 2009

Senior Member

Hello,

Oracle treats an empty string for Varchar2 columns as null. You could use a char type instead, but I'm not sure why you are using a not-null constraint on a field that seems to require allowing empty data. Wouldn't allowing null work? EclipseLink is able to convert nulls it reads from the database into a default value via the setNullValue api on DatabaseMapping, as described at: http://wiki.eclipse.org/Configuring_a_Mapping_%28ELUG%29#Con figuring_a_Default_Null_Value_at_the_Mapping_Level

Unfortunately I do not know if this is available from annotations, so you may need to use a customizer to get the mapping.

Best Regards,
Chris

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