Reinier Olislagers wrote / napísal(a):
On 18-4-2012 8:27, LacaK wrote:
I don't have Delphi with dbExpress here, so can't test.
I did some tests in Delphi XE with DBExpress and MySQL:
for stTables column names are: CatalogName, SchemaName, TableName,
TableType ('TABLE')
So difference with FPC: the names (catalog_name, schema_name,
table_name, table_type). The FPC names seem to match the ISO SQL*) names
more (ISO has them capitalized, no problem if no quotes are used).
In contrast to dbExpress (and probably the standard), FPC also has recno
(internal database object ID? Could be very handy.)
Other difference: TableType ('TABLE'): I think Delphi+dbExpress better
match ISO SQL*) here (though 'BASE TABLE', 'VIEW') instead of the 0 that
FPC returns - at least in the Firebird, PostgreSQL connectors that I
checked.
*) at least an SQL2008 draft version I found some time ago...
The PostgreSQL documentation is also very nice:
http://www.postgresql.org/docs/current/static/information-schema.html
As is the Mimer (link to old documentation; newer is inside a frame):
http://developer.mimer.com/documentation/html_91/Mimer_SQL_Engine_DocSet/Data_dic_views2.html
I'd prefer changing TABLE_TYPE to the ISO way of doing things, but of
course it could break existing applications if any of them use this
functionality... Still, FPC always returns 0 so I suppose it would have
been useless anyway, so no harm in changing it.
Thinking about column names I would suggest, change it according to
SQL-Standard (information_schema views). To be fully compatible.
(because ATM we are not compatible with SQL-Standard NOR Delphi)
Advantage will be, that we will be able do for example 'select * from
INFORMATION_SCHEMA.TABLES'
so if some DB provides also other columns (additional information on
tables, procedures, indexes, columns etc.) we will get it.
It will of course lead to breaking backward compatibility, but I think,
that there is very, very (if any) small amount of users, which use
setschemainfo+open to get metadata information.
L.
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