On 22/11/2011 11:50, Lukas Masak (JIRA) wrote: > computed index by substring function for long columns > ----------------------------------------------------- > > Key: CORE-3672 > URL: http://tracker.firebirdsql.org/browse/CORE-3672 > Project: Firebird Core > Issue Type: Bug > Affects Versions: 2.1.4 > Environment: win32 > Reporter: Lukas Masak > Priority: Minor > > > It is not possible to use substring function to create computed index for > large columns. > > CREATE INDEX IDX1 ON tbl_test COMPUTED BY (SUBSTRING(col1 from 1 for 20)) > will fail with message: key size exceeds implementation restriction for index > "IDX1" > > select char_length( SUBSTRING(col1 from 1 for 20)) from tbl_test returns > 20 so I was expecting index to work. > > workaround > CREATE INDEX IDX1 ON tbl_test COMPUTED BY (CAST(SUBSTRING(col1 from 1 for 20) > as varchar(20))) > This issue depends if we're allowed to change SUBSTRING with constant length to describe the result with that length instead of the value one, like we do with *PAD.
Accordingly to the standard, substring "should" be described as returning the same type of the value. Adriano ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
