From d9790a406c69a46eb197cea725c1e7c7e480ac41 Mon Sep 17 00:00:00 2001
From: "heikki@hundin.mysql.fi" <>
Date: Mon, 9 Feb 2004 23:57:29 +0200
Subject: row0mysql.c:   Allow always DROPping of a table which is only
 referenced by FOREIGN KEY constraints from the same table Many files:   Do
 not let REPLACE to perform internally an UPDATE if the table is referenced by
 a FOREIGN KEY: the manual says that REPLACE must resolve a duplicate key
 error semantically with DELETE(s) + INSERT, and not by an UPDATE; the
 internal update caused foreign key checks and cascaded operations to behave
 in a semantically wrong way

---
 sql/sql_insert.cc | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

(limited to 'sql/sql_insert.cc')

diff --git a/sql/sql_insert.cc b/sql/sql_insert.cc
index 97b7c1db03d..4d7a9f7e508 100644
--- a/sql/sql_insert.cc
+++ b/sql/sql_insert.cc
@@ -442,7 +442,15 @@ int write_record(TABLE *table,COPY_INFO *info)
 						HA_READ_KEY_EXACT))))
 	  goto err;
       }
-      if (last_uniq_key(table,key_nr))
+      /*
+	The manual defines the REPLACE semantics that it is either an INSERT or
+	DELETE(s) + INSERT; FOREIGN KEY checks do not function in the defined
+	way if we allow MySQL to convert the latter operation internally to an
+	UPDATE.
+      */
+
+      if (last_uniq_key(table,key_nr)
+	  && !table->file->referenced_by_foreign_key())
       {
 	if ((error=table->file->update_row(table->record[1],table->record[0])))
 	  goto err;
-- 
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