Hi, > I don't understand the sqlite command "alter table add column". Please help > me! > > I have the following 2 tables: > > TABLEONE(columnA INTEGER PRIMARY KEY, columnB TEXT); > > TABLETWO(columnX INTEGER PRIMARY KEY, columnY TEXT); > > I want to add a new column "cloumnZ" to TABLETWO. The new column must be a > foreignkey and references to columnA!
If you look at the documentation (http://www.sqlite.org/lang_altertable.html), it says: It is not possible to rename a column, remove a column, or add or remove constraints from a table. The usual way to achieve this is to rename the existing table, recreate the table with the new column and constraint, and copy the data from the old table: ALTER TABLE TABLETWO RENAME TO OLD_TABLETWO; CREATE TABLE TABLETWO (...); INSERT INTO TABLETWO (columnX, columnY, columnZ) SELECT (columnX, columnY, ...); You may or may not do the final step of: DROP TABLE OLD_TABLETWO; I generally do this step a bit later, when I'm really really sure everything worked fine. You need to decide how you want to populate ColumnZ in TABLETWO. Hope this helps, Neil _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
