From 9c6c44835321a6331cd68080327899349083b25a Mon Sep 17 00:00:00 2001
From: AKhatskevich <avkhatskevich@tarantool.org>
Date: Mon, 8 Oct 2018 19:26:59 +0300
Subject: [PATCH] sql: fix fk set null clause
After changing behavior of the `IS` operator (#b3a3ddb571),
`SET NULL` was rewritten to use `EQ` instead. Which doesn't respect
NULLs.
This commit fixes the null related behavior by emitting logical
constructions equivalent for this case to old `IS`.
The new expression works differently than old `IS` for nulls, however
the difference doesn't change anything, because matched rows are then
searched in a child table with `EQ` expression which do not match nulls.
Before:
`oldval` old_is `newval`
Now:
`oldval` is_null or (`newval` is_not_null and `oldval` eq `newval`)
Closes #3645
---
src/box/sql/fkey.c | 43 +++++++++++++++++++++++++------------
test/sql-tap/fkey1.test.lua | 25 ++++++++++++++++++++-
2 files changed, 53 insertions(+), 15 deletions(-)
diff --git a/src/box/sql/fkey.c b/src/box/sql/fkey.c
index 091778fc85..56885e448f 100644
--- a/src/box/sql/fkey.c
+++ b/src/box/sql/fkey.c
@@ -787,24 +787,39 @@ fkey_action_trigger(struct Parse *pParse, struct Table *pTab, struct fkey *fkey,
/*
* For ON UPDATE, construct the next term of the
- * WHEN clause. The final WHEN clause will be like
+ * WHEN clause, which should return false in case
+ * there is a reason to for a broken constrant in
+ * a parent table:
+ * no_action_needed := `oldval` IS NULL OR
+ * (`newval` IS NOT NULL AND
+ * `newval` = `oldval`)
+ *
+ * The final WHEN clause will be like
* this:
*
- * WHEN NOT(old.col1 = new.col1 AND ... AND
- * old.colN = new.colN)
+ * WHEN NOT( no_action_needed(col1) AND ...
+ * no_action_needed(colN))
*/
if (is_update) {
- struct Expr *l, *r;
- l = sqlite3PExpr(pParse, TK_DOT,
- sqlite3ExprAlloc(db, TK_ID, &t_old, 0),
- sqlite3ExprAlloc(db, TK_ID, &t_to_col,
- 0));
- r = sqlite3PExpr(pParse, TK_DOT,
- sqlite3ExprAlloc(db, TK_ID, &t_new, 0),
- sqlite3ExprAlloc(db, TK_ID, &t_to_col,
- 0));
- eq = sqlite3PExpr(pParse, TK_EQ, l, r);
- when = sqlite3ExprAnd(db, when, eq);
+ struct Expr *old_val = sqlite3PExpr(pParse, TK_DOT,
+ sqlite3ExprAlloc(db, TK_ID, &t_old, 0),
+ sqlite3ExprAlloc(db, TK_ID, &t_to_col, 0));
+ struct Expr *new_val = sqlite3PExpr(pParse, TK_DOT,
+ sqlite3ExprAlloc(db, TK_ID, &t_new, 0),
+ sqlite3ExprAlloc(db, TK_ID, &t_to_col, 0));
+ struct Expr *old_is_null = sqlite3PExpr(
+ pParse, TK_ISNULL,
+ sqlite3ExprDup(db, old_val, 0), NULL);
+ eq = sqlite3PExpr(pParse, TK_EQ, old_val,
+ sqlite3ExprDup(db, new_val, 0));
+ struct Expr *new_non_null =
+ sqlite3PExpr(pParse, TK_NOTNULL, new_val, NULL);
+ struct Expr *non_null_eq =
+ sqlite3PExpr(pParse, TK_AND, new_non_null, eq);
+ struct Expr *no_action_needed =
+ sqlite3PExpr(pParse, TK_OR, old_is_null,
+ non_null_eq);
+ when = sqlite3ExprAnd(db, when, no_action_needed);
}
if (action != FKEY_ACTION_RESTRICT &&
diff --git a/test/sql-tap/fkey1.test.lua b/test/sql-tap/fkey1.test.lua
index 3c29b097df..b419e4d591 100755
--- a/test/sql-tap/fkey1.test.lua
+++ b/test/sql-tap/fkey1.test.lua
@@ -1,6 +1,6 @@
#!/usr/bin/env tarantool
test = require("sqltester")
-test:plan(18)
+test:plan(25)
-- This file implements regression tests for foreign keys.
@@ -233,4 +233,27 @@ test:do_execsql_test(
-- </fkey1-6.3>
})
+-- gh-3645: update col=Null do not activates ON UPDATE trigger.
+
+test:do_select_tests(
+ "fkey1-7",
+ {
+ {"0",
+ [[
+ CREATE TABLE T12 (A INTEGER PRIMARY KEY,
+ B CHAR(5) UNIQUE);
+ CREATE TABLE T13 (A INTEGER PRIMARY KEY,
+ B CHAR(5) UNIQUE,
+ FOREIGN KEY (B) REFERENCES T12 (B) ON UPDATE SET NULL);
+ INSERT INTO T12 VALUES (1,'a');
+ INSERT INTO T13 VALUES (1,'a');
+ ]], {}},
+ {"1", "UPDATE T12 SET B = NULL", {}},
+ {"2", "SELECT * FROM T12", {1, ""}},
+ {"3", "SELECT * FROM T13", {1, ""}},
+ {"4", "UPDATE T12 SET B = 'a'", {}},
+ {"5", "SELECT * FROM T12", {1, "a"}},
+ {"6", "SELECT * FROM T13", {1, ""}},
+ })
+
test:finish_test()
--
GitLab