Ho, How do qgis to analyze the table to retrieve the unique? A loop on every record or a SQL to count distinct ?
A. Il 04/set/2015 08:01, "Bernhard Ströbl" <bernhard.stro...@jena.de> ha scritto: > > > 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 > > > __________ Information from ESET Mail Security, version of virus signature > database 12200 (20150904) __________ > > The message was checked by ESET Mail Security. > http://www.eset.com > > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user >
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