Would you consider implementing this not as a pragma, but as a real statement, 
like MySQL's SHOW COLUMNS 
(https://dev.mysql.com/doc/refman/5.5/en/show-columns.html)? Would be easier to 
memorize.

----- Original Message ----- 
From: Keith Medcalf <kmedc...@dessus.com>
To: SQLite mailing list <sqlite-users@mailinglists.sqlite.org>
Sent: Wednesday, August 14, 2019, 00:36:07
Subject: [sqlite] Determining column collating functions


On Tuesday, 13 August, 2019 15:59, Manuel Rigger <rigger.man...@gmail.com> 
wrote:

>Is there a simple way to determine the collating function of a
>column?

Presently, there is not.

>PRAGMA table_info does not seem to provide this information. The
>information could be extracted from sqlite_master, which contains the
>SQL statements used to create the table or view. While parsing the
>SQL string is rather straightforward for tables, it would involve 
>more effort to determine the collating functions for views, which 
>can again reference other views or tables.

The internal schema representation for the column (from which the table_info 
and table_xinfo draw their information) does contain the name of the collation 
being used if it is not the default (and also the actual affinity of the 
column), however the current table_info/table_xinfo does not return that 
information, although modifications to do so would be rather trivial.

Richard, would you like a patch for this (and a database_info pragma, which 
would allow all the introspection pragma tables to work across all attached 
databases more easily)?

As for views, they are a sort of dynamic thing so the collating sequence (nor 
the affinity) of a view column is not known until the statement using the view 
is prepared (a view is merely the storage of a definition and nothing is really 
known about it until it is used).

-- 
The fact that there's a Highway to Hell but only a Stairway to Heaven says a 
lot about anticipated traffic volume.





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