From 63847496f14c813a5d80efd5b7de0f1294ffe1e3 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 13 Apr 2024 16:07:11 +0200 Subject: Adding upstream version 3.45.1. Signed-off-by: Daniel Baumann --- www/lang_conflict.html | 294 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 294 insertions(+) create mode 100644 www/lang_conflict.html (limited to 'www/lang_conflict.html') diff --git a/www/lang_conflict.html b/www/lang_conflict.html new file mode 100644 index 0000000..2fea7d9 --- /dev/null +++ b/www/lang_conflict.html @@ -0,0 +1,294 @@ + + + + + +The ON CONFLICT Clause + + + +
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+Small. Fast. Reliable.
Choose any three. +
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+The ON CONFLICT Clause +
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conflict-clause: +

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+ + + + + + +ON + + + +CONFLICT + + + +ROLLBACK + +ABORT + +FAIL + +IGNORE + +REPLACE + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
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The ON CONFLICT clause is a +non-standard extension specific to SQLite +that can appear in many other SQL commands. +It is given its own section in this document because it is not +part of standard SQL and therefore might not be familiar.

+ +

The ON CONFLICT clause described here has been a part of +SQLite since before version 3.0.0 (2004-06-18). The phrase +"ON CONFLICT" is also part of UPSERT, which is an extension +to INSERT added in version 3.24.0 (2018-06-04). Do not +confuse these two separate uses of the "ON CONFLICT" phrase. + +

The syntax for the ON CONFLICT clause is as shown above for +the CREATE TABLE command. For the INSERT and +UPDATE commands, the keywords "ON CONFLICT" are replaced by "OR" so that +the syntax reads more naturally. For example, instead of +"INSERT ON CONFLICT IGNORE" we have "INSERT OR IGNORE". +The keywords change but the meaning of the clause is the same +either way.

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The ON CONFLICT clause applies to UNIQUE, NOT NULL, +CHECK, and PRIMARY KEY constraints. +The ON CONFLICT algorithm does not +apply to FOREIGN KEY constraints. +There are five conflict resolution algorithm choices: +ROLLBACK, ABORT, FAIL, IGNORE, and REPLACE. +The default conflict resolution algorithm is ABORT. This +is what they mean:

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ROLLBACK
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When an applicable constraint violation occurs, the ROLLBACK +resolution algorithm aborts the current SQL statement with +an SQLITE_CONSTRAINT error and rolls back the current transaction. +If no transaction is +active (other than the implied transaction that is created on every +command) then the ROLLBACK resolution algorithm works the same as the +ABORT algorithm.

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ABORT
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When an applicable constraint violation occurs, the ABORT +resolution algorithm aborts the current SQL statement +with an SQLITE_CONSTRAINT error and backs out any changes +made by the current SQL statement; but changes caused +by prior SQL statements within the same transaction are preserved and the +transaction remains active. +This is the default behavior and the behavior specified by the SQL +standard.

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FAIL
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When an applicable constraint violation occurs, the FAIL +resolution algorithm aborts the current SQL statement with an +SQLITE_CONSTRAINT error. But the FAIL resolution does not +back out prior changes of the SQL statement that failed nor does +it end the transaction. +For example, if an UPDATE +statement encountered a constraint violation on the 100th row that +it attempts to update, then the first 99 row changes are preserved +but changes to rows 100 and beyond never occur.

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The FAIL behavior only works for uniqueness, NOT NULL, and CHECK +constraints. A foreign key constraint violation causes an ABORT. +

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IGNORE
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When an applicable constraint violation occurs, +the IGNORE resolution algorithm skips the one row that contains +the constraint violation and continues processing subsequent rows +of the SQL statement as if nothing went wrong. +Other rows before and after the row that +contained the constraint violation are inserted or updated +normally. No error is returned for uniqueness, NOT NULL, and +UNIQUE constraint errors when the IGNORE conflict resolution +algorithm is used. However, the IGNORE conflict resolution +algorithm works like ABORT for foreign key constraint errors. +

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REPLACE
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When a UNIQUE or PRIMARY KEY constraint violation occurs, +the REPLACE algorithm +deletes pre-existing rows that are causing the constraint violation +prior to inserting or updating the current row and the command continues +executing normally. +If a NOT NULL constraint violation occurs, the REPLACE conflict +resolution replaces the NULL value with +the default value for that column, or if the column has no default +value, then the ABORT algorithm is used. +If a CHECK constraint or foreign key constraint violation occurs, +the REPLACE conflict resolution algorithm works like ABORT.

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When the REPLACE conflict resolution strategy deletes rows in order to +satisfy a constraint, delete triggers fire if and only if +recursive triggers are enabled.

+ +

The update hook is not invoked for rows that +are deleted by the REPLACE conflict resolution strategy. Nor does +REPLACE increment the change counter. +The exceptional behaviors defined in this paragraph might change +in a future release.

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The algorithm specified in the OR clause of an INSERT or UPDATE +overrides any algorithm specified in a CREATE TABLE. +If no algorithm is specified anywhere, the ABORT algorithm is used.

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This page last modified on 2022-04-18 02:55:50 UTC

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