On Sun, Oct 10, 2010 at 2:45 AM, Fadhel Al-Hashim <fad...@gmail.com> wrote: > Good day, > > is it possible to Alter a table and add a unique constraint on one or more > columns? >
See http://www.sqlite.org/lang_altertable.html In particular -- "The ADD COLUMN syntax is used to add a new column to an existing table. The new column is always appended to the end of the list of existing columns. The column-def rule defines the characteristics of the new column. The new column may take any of the forms permissible in a CREATE TABLE statement, with the following restrictions: The column may not have a PRIMARY KEY or UNIQUE constraint. The column may not have a default value of CURRENT_TIME, CURRENT_DATE, CURRENT_TIMESTAMP, or an expression in parentheses. If a NOT NULL constraint is specified, then the column must have a default value other than NULL. If foreign key constraints are enabled and a column with a REFERENCES clause is added, the column must have a default value of NULL. Note also that when adding a CHECK constraint, the CHECK constraint is not tested against preexisting rows of the table. This can result in a table that contains data that is in violation of the CHECK constraint. Future versions of SQLite might change to validate CHECK constraints as they are added." > thanks, > > fadhel > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- Puneet Kishor http://www.punkish.org Carbon Model http://carbonmodel.org Charter Member, Open Source Geospatial Foundation http://www.osgeo.org Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor Nelson Institute, UW-Madison http://www.nelson.wisc.edu ----------------------------------------------------------------------- Assertions are politics; backing up assertions with evidence is science ======================================================================= _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
