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Command: sqlite3_changes | Section: 3 | Source: NetBSD | File: sqlite3_changes.3
SQLITE3_CHANGES(3) FreeBSD Library Functions Manual SQLITE3_CHANGES(3)
NAME
sqlite3_changes - Count The Number Of Rows Modified
SYNOPSIS
int
sqlite3_changes(sqlite3*);
DESCRIPTION
This function returns the number of rows modified, inserted or deleted by
the most recently completed INSERT, UPDATE or DELETE statement on the
database connection specified by the only parameter. Executing any other
type of SQL statement does not modify the value returned by this
function.
Only changes made directly by the INSERT, UPDATE or DELETE statement are
considered - auxiliary changes caused by triggers, foreign key actions
or REPLACE constraint resolution are not counted.
Changes to a view that are intercepted by INSTEAD OF triggers are not
counted. The value returned by sqlite3_changes() immediately after an
INSERT, UPDATE or DELETE statement run on a view is always zero. Only
changes made to real tables are counted.
Things are more complicated if the sqlite3_changes() function is executed
while a trigger program is running. This may happen if the program uses
the changes() SQL function, or if some other callback function invokes
sqlite3_changes() directly. Essentially:
o Before entering a trigger program the value returned by
sqlite3_changes() function is saved. After the trigger program has
finished, the original value is restored.
o Within a trigger program each INSERT, UPDATE and DELETE statement
sets the value returned by sqlite3_changes() upon completion as
normal. Of course, this value will not include any changes performed
by sub-triggers, as the sqlite3_changes() value will be saved and
restored after each sub-trigger has run.
This means that if the changes() SQL function (or similar) is used by the
first INSERT, UPDATE or DELETE statement within a trigger, it returns the
value as set when the calling statement began executing. If it is used
by the second or subsequent such statement within a trigger program, the
value returned reflects the number of rows modified by the previous
INSERT, UPDATE or DELETE statement within the same trigger.
If a separate thread makes changes on the same database connection while
sqlite3_changes() is running then the value returned is unpredictable and
not meaningful.
SEE ALSO
sqlite3_changes(3), sqlite3_total_changes(3)
FreeBSD 14.1-RELEASE-p8 December 19, 2018 FreeBSD 14.1-RELEASE-p8