Am 03.09.2015 um 23:41 schrieb Sandro Santilli:
On Wed, Sep 02, 2015 at 08:48:34AM +0200, Bernhard Ströbl wrote:
Am 01.09.2015 um 17:49 schrieb Matthias Kuhn:
2. If there are tables without a PK open a second modal dialog with an
explanation of the problem and offer to select a pk from a combobox.
I hope you mean "relation" not table, a table should always have a
PK.
It's not mandatory for a table to have a PK.
I guess by "tables without a PK" he means table for which no PRIMARY
KEY constraint is explicitly defined (should an UNIQUE key be
considered equally valid?).
It is not mandatory, of course, that's why I wrote "should", but IMHO it
is very bad database design to not define one.
There might be several UNIQUE constraints on one table but there can be
only one PK constraint. So in case of only a UINIQUE constraint the
table would be handled as any other without PK constraint (or QGIS needs
to analyse how many fields have a UNIQUE constraint).
Bernhard
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