Bug#12626844 : WE ARE NOT CHECKING VIEW TABLE NAMES

               ENOUGH - CONCAT() HACKS. ALSO WRONG
               ERROR MESSAGE WHILE TRYING TO CREATE
               A VIEW ON A NON EXISTING DATABASE

PROBLEM:
The first part of the problem is concluded as not a
bug, as 'concat' is not a reserved word and it is
completely valid to create a view with the name
'concat'.

The second issue is, while trying to create a view on
a non existing database, we are not giving a proper error
message.

FIX:
We have added a check for the database existence while
trying to create a view. This check would give an error
as 'unknown database' when the database does not exist.

This patch is a backport of the patch for Bug#13601606

mysql-test/r/view.result

@@ -4102,3 +4102,10 @@ UNLOCK TABLES;
 # Connection default
 DROP PROCEDURE p1;
 DROP TABLE t1;
+#
+# Bug#12626844: WRONG ERROR MESSAGE WHILE CREATING A VIEW ON A
+#               NON EXISTING DATABASE
+#
+DROP DATABASE IF EXISTS nodb;
+CREATE VIEW nodb.a AS SELECT 1;
+ERROR 42000: Unknown database 'nodb'

mysql-test/t/view.test

@@ -4136,6 +4136,17 @@ disconnect con2;
 disconnect con3;
 
 
+--echo #
+--echo # Bug#12626844: WRONG ERROR MESSAGE WHILE CREATING A VIEW ON A
+--echo #               NON EXISTING DATABASE
+--echo #
+
+--disable_warnings
+DROP DATABASE IF EXISTS nodb;
+--enable_warnings
+--error ER_BAD_DB_ERROR
+CREATE VIEW nodb.a AS SELECT 1;
+
 # Check that all connections opened by test cases in this file are really
 # gone so execution of other tests won't be affected by their presence.
 --source include/wait_until_count_sessions.inc

sql/sql_view.cc

@@ -444,6 +444,13 @@ bool mysql_create_view(THD *thd, TABLE_LIST *views,
 
   view= lex->unlink_first_table(&link_to_local);
 
+  if (check_db_dir_existence(view->db))
+  {
+    my_error(ER_BAD_DB_ERROR, MYF(0), view->db);
+    res= TRUE;
+    goto err;
+  }
+
   if (mode == VIEW_ALTER && fill_defined_view_parts(thd, view))
   {
     res= TRUE;