RE: Fastest way to get a unique identifier/tracking column changes

["Reeve" <news@xxxxxxxxxx>]

Bonjour Richard,

This is almost perfect: on V5R2, ROWID generates a 40-character
variable-length field with an allocated length of 26.  Unfortunately, it
takes up a lot of space, and I'll be dealing with a large number of
records...and using a literal is harder than usual.  

Thanks,
Reeve

> -----Original Message-----
> From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-
> bounces@xxxxxxxxxxxx] On Behalf Of Richard Theis
> Sent: Tuesday, July 13, 2004 3:36 AM
> To: midrange-l@xxxxxxxxxxxx
> Subject: RE: Fastest way to get a unique identifier/tracking column
> changes
> 
> 
> 
> 
> 
> 
> Reeve wrote:
> > I though the "IDENTITY" value was table-specific, not global.
> Therefore,
> to
> > track changes from multiple tables in one "historical tracking" table,
> I'd
> > need to identify each tracking record by table and identity value.
> 
> Check the SQL type ROWID, it is unique across all DB2 UDB for
> iSeries/zSeries .
> 
> >From Information Center:
> 
> A row ID is a value that uniquely identifies a row in a table. A column or
> a host variable can have a row ID data type. A ROWID column enables
> queries
> to be written that navigate directly to a row in the table. Each value in
a
> ROWID column must be unique. The database manager maintains the
> values
> permanently, even across table reorganizations. When a row is inserted
> into
> the table, the database manager generates a value for the ROWID
> column
> unless one is supplied. If a value is supplied, it must be a valid row ID
> value that was previously generated by either DB2 UDB for OS/390 and
> z/OS
> or DB2 UDB for iSeries. The internal representation of a row ID value is
> transparent to the user. The value is never subject to CCSID conversion
> because it is considered to contain BIT data. The length attribute of a
> ROWID column is 40.
> Using ROWID is another way to have the system assign a unique value to
> a
> column in a table. ROWID is similar to identity columns, but rather than
> being an attribute of a numeric column, it is a separate data type. To
> create a table similar to the identity column example:
> 
> 
>  CREATE TABLE ORDERS
>     (ORDERNO ROWID
>     GENERATED ALWAYS,
>     SHIPPED_TO VARCHAR (36) ,
>     ORDER_DATE DATE)
> 
> 
> 
>  Bonne réception/Best regards
>  Richard THEIS
>    Education iSeries 400, Sce 8075, MTG
>    01.49.14.46.34 /  Fax 01.43.04.59.85
>    theis_richard@xxxxxxxxxx
> 
> 
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