Ed Bagdonas wroze:
> 
> We are attempting to use Apache Torque 3.1 (java persistence 
> layer) with
> MaxDb 7.5.  
> 
>  
> 
> Torque generated select distinct queries to the database to get a list
> of objects for manipulation look like:
> 
> SELECT DISTINCT foo.PKEY, foo.USERSID, foo.DESCRIPTION FROM 
> foo ORDER BY
> foo.PKEY 
> 
>  
> 
> Torque propagates an exception from the database:  
> 
> SQL statement not allowed for column of data type LONG:DESCRIPTION
> 
>  
> 
> According the SapDB documentation DISTINCT is not supported 
> on long byte
> / longtext columns. 
> 
>  
> 
> I am sort of curious why this is the case - what if it were 
> required?  
> 

The check for distinctness of a column of up to 2 GB is a little bit harder than
the check for any other column. We did not implement it as we did not expect people
to store  book-texts/images in LONG-columns and than to check for the distinctness
of them.

> Is there a work-around?  In our case the DESCRIPTION field is 
> varies in
> size from 0 to ~2K bytes.
> 
change column description to a CHAR/VARCHAR-column (2000) or the like.
I hope that this column (together with the others) will not exceed the maximum row 
length
of nearly 8KB.

Elke
SAP Labs Berlin

> 
> (Note that the data was created through maxdbproxy from a previously
> existing MySqlMaxNt database, and that 
> 
> the longtext column type was created from the mysql text type. )
> 
>  
> 
> 

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