qualifier never matches correlation_name

[Marco Molinaro]

Hi Walter, hi all,
from the grammar point of view it seems correct because the
[ <schema_name> <period> ]
in the <table_name> rule is optional and there are no other
grammar rules that will suffer from it, the only other places
the <qualifier> is used being

<select_sublist> ::= <derived_column> | <qualifier> <period> <asterisk>
<column_reference> ::= [ <qualifier> <period> ] <column_name>

My thought, however, is that table names and correlation names are
different concepts in SQL, so my choice would be not to simplify that rule,
simplification that sounds to me like implicitly meaning that a correlation
name is the same as an unqualified table name (when used as a qualifier).

Cheers,
     Marco

2015-01-13 22:23 GMT+01:00 Walter Landry <wlandry at caltech.edu>:

> Hello Everyone,
>
> In ADQL, the rules for qualifier, table_name, and correlatio_name are
>
>   <qualifier> ::= <table_name> | <correlation_name>
>   <table_name> ::= [ <schema_name> <period> ] <identifier>
>   <correlation_name> ::= <identifier>
>
> It seems that table_name matches everything that correlation_name
> matches.  If so, couldn't we simplify the grammar by making
>
>   <qualifier> ::= <table_name>
>
> This seems to be something that is inherited from SQL 92
>
>   http://savage.net.au/SQL/sql-92.bnf.html#qualifier
>
> so we probably can not fix it.  I just wanted to make sure I
> understand the grammar.
>
> Thanks,
> Walter Landry
>
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