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Re: JDBC and arrays

From: Russell Francis <rfrancis(at)ev(dot)net>
To: Miroslav Šulc <miroslav(dot)sulc(at)startnet(dot)cz>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: JDBC and arrays
Date: 2007-02-02 14:40:39
Message-ID: 45C34D67.6000509@ev.net (view raw or flat)
Thread:
Lists: pgsql-jdbc
Miroslav Šulc wrote:
> Thank you for explanation. If I still want to write inet[] data, is it
> sufficient to implement PGobject so it returns 'inet[]' type and '{
> "ip", "ip" }' value and pass that to setObject()?

Miroslav,

I don't know if this will help you but awhile ago I implemented data
types for the JDBC driver for PGinet, PGmacaddr, PGcidr which have been
used successfully by a number of people including myself ;)  I would
still like to get them integrated into the driver but haven't had much
time to pursue it.  You can find the current version at

http://oak.cats.ohiou.edu/~rf358197/jdbc/2/

I have zero experience using them in an array but if you are using those
data types in PostgreSQL and using Java, the code might be useful to you.

Kind regards,
Russ

> 
> -- 
> Miroslav Šulc
> 
> 
> 
> Kris Jurka napsal(a):
>>
>>
>> On Fri, 2 Feb 2007, Miroslav Šulc wrote:
>>
>>> I tried to find some info on how to work with arrays using PostgreSQL
>>> JDBC driver but didn't find anything useful except that I can
>>> implement java.sql.Array to get support for arrays. Can someone,
>>> please, send me a link on how to write and read array data using
>>> PostgreSQL JDBC driver or give me a brief explanation? I'm also
>>> interested how to work with inet[] arrays as they do not seem to be
>>> directly supported by JDBC API.
>>
>> Reading arrays is pretty straightforward:
>>
>> ResultSet rs = stmt.executeQuery("SELECT '{a,b}'::text[]");
>> rs.next();
>> Array arr = rs.getArray(1);
>> String s[] = (String)arr.getArray();
>>
>> Writing arrays is not easy because prior to the JDBC4 spec there was
>> no way to create java.sql.Array objects without creating a class that
>> implements java.sql.Array yourself.  Now JDBC4 offers
>> Connection.createArrayOf() which unfortunately we haven't implemented
>> yet. So while there is a light at the end of the tunnel you're still
>> stuck implementing java.sql.Array yourself.  Check the mailing list
>> for examples of that.
>>
>> Currently arrays of non-standard datatypes like inet are not
>> supported. Seems possible to do if you were willing to use PGobject
>> for unknown types, but no one has done it.
>>
>> Also more complicated things like multi-dimensional arrays are note
>> supported.
>>
>> Kris Jurka
>> ---------------------------(end of broadcast)---------------------------
>> TIP 4: Have you searched our list archives?
>>
>>               http://archives.postgresql.org
> 
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