Task list database table

Furthermore, to automatically maintain consistency, a constraint must be added to the table as well so that when the original task is deleted, the corresponding task in this table is deleted as well. However, when the table is created using the AS-SELECT statement, the constraint cannot implemented yet as it cannot be part of the statement as can be seen from the syntax diagram above. Therefore, after the table is created, the table must be [http://www.sqlite.org/lang_altertable.html altered] to create a reference to the original task in the [[Tasks database table|tasks table]]. However, the [www.sqlite.org SQLite] only supports a limited subset of [http://www.sqlite.org/lang_altertable.html ALTER TABLE] and (amongst other) does not allow adding constraints to a table. Therefore, to implement the constraint, an additional column <tt>Parent</tt> is added that is referenced to the <tt>Id</tt> of the [[Tasks_database_table|tasks table]]. After creating this column, it must still be filled with the same value as the <tt>Id</tt>.

Furthermore, to automatically maintain consistency, a constraint must be added to the table as well so that when the original task is deleted, the corresponding task in this table is deleted as well. However, when the table is created using the AS-SELECT statement, the constraint cannot implemented yet as it cannot be part of the statement as can be seen from the syntax diagram above. Therefore, after the table is created, the table must be [http://www.sqlite.org/lang_altertable.html altered] to create a reference to the original task in the [[Tasks database table|tasks table]]. However, the [www.sqlite.org SQLite] only supports a limited subset of [http://www.sqlite.org/lang_altertable.html ALTER TABLE] and (amongst other) does not allow adding constraints to a table. Therefore, to implement the constraint, an additional column <tt>Parent</tt> is added that is referenced to the <tt>Id</tt> of the [[Tasks_database_table|tasks table]]. After creating this column, it must still be filled with the same value as the <tt>Id</tt>.

== Implementation ==

== Implementation ==