Is it possible to insert the specified value in autoincrement column? - sqlite

Question

I need to copy one table to another and both tables contain column with AUTOINCREMENT. Is it possible to insert a defined value into AUTOINCREMENT column.
Tables:
CREATE TABLE tmptimetables (
_id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
_title NVARCHAR(256) NOT NULL,
_weeks INTEGER NOT NULL,
_first_week_date INTEGER NOT NULL,
_auto_complete INTEGER NOT NULL,
_first_lesson_time INTEGER NOT NULL,
_lesson_duration INTEGER NOT NULL,
_break_duration INTEGER NOT NULL,
_color INTEGER NOT NULL,
_symbol NCHAR(1) NOT NULL
);
CREATE TABLE timetables (
id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
title NVARCHAR(256) NOT NULL,
weeks INTEGER NOT NULL,
first_week_date INTEGER NOT NULL,
auto_complete INTEGER NOT NULL,
first_lesson_time INTEGER NOT NULL,
lesson_duration INTEGER NOT NULL,
break_duration INTEGER NOT NULL,
color INTEGER NOT NULL,
symbol NCHAR(1) NOT NULL
);
My SQL request:
INSERT INTO timetables (
auto_complete,
break_duration,
color,
first_lesson_time,
first_week_date, id,
lesson_duration,
symbol,
title,
weeks
)
SELECT
_auto_complete,
_break_duration,
_color,
_first_lesson_time,
_first_week_date,
_id,
_lesson_duration,
_symbol,
_title,
_weeks
FROM tmptimetables

Answer 1

AUTOINCREMENT can only be used for a column that is INTEGER PRIMARY KEY, it is INTEGER PRIMARY KEY that is the factor that makes the column a special column whereby if the value is not provided when inserting a row that a unique integer will be assigned.
So be the column INTEGER PRIMARY KEY or INTEGER PRIMARY KEY AUTOINCREMENT you can specify an integer value and a row may be inserted with the given value.
A row will not be inserted with a given value if that value is not unique.
For example if the table timetables is currently :-
Then
INSERT INTO timetables (id,title,weeks,first_week_date,auto_complete,first_lesson_time,lesson_duration,break_duration,color,symbol) VALUES (null,'mytitle',78,86000,23,1800,900,200,16,'E');
Would insert a new row with the id as determined by SQLite's algorithm for providing a unique id (probably 5).
If the id were changed to be provided (i.e. not null) say to 10 as per :-
INSERT INTO timetables (id,title,weeks,first_week_date,auto_complete,first_lesson_time,lesson_duration,break_duration,color,symbol) VALUES (10,'mytitle',78,86000,23,1800,900,200,16,'E');
Then the id for the new row would be 10.
However if then using (the same SQL but with the last column value changed) :-
INSERT INTO timetables (id,title,weeks,first_week_date,auto_complete,first_lesson_time,lesson_duration,break_duration,color,symbol) VALUES (10,'mytitle',78,86000,23,1800,900,200,16,'Z');
A new row would not be inserted as a row with an id of 10 already exists.
Finally if the id is not given (null is used) but the SQL is otherwise the same a new row is inserted with a unique id being provided by SQLite e.g.
INSERT INTO timetables (id,title,weeks,first_week_date,auto_complete,first_lesson_time,lesson_duration,break_duration,color,symbol) VALUES (null,'mytitle',78,86000,23,1800,900,200,16,'Z');
So the end result of following the above is :-
AUTOINCREMENT
The AUTOINCREMENT keyword, only usable for an INTEGER PRIMARY COLUMN, invokes a different algorithm for determining the next sequence to ensure that the next sequence/id is always greater, whilst without AUTOINCREMENT a lower sequence/id can be applied.
The AUTOINCREMENT keyword does not specify that if a value for the column is not provided then a sequence/id is applied it is INTEGER PRIMARY KEY that specifies that. Well actually, by default, i.e. unless WITHOUT ROWID is specified, this happens for all tables. It's just the the special rowid column is hidden. Specifying <column_name> INTEGER PRIMARY KEY (where is a valid column name) creates an alias of the rowid.
For example using SELECT rowid,* FROM timetables produces :-
SQLite Autoincrement
Rowid Tables