diff --git a/manifest b/manifest
index 23bb4d825d..073e81e98d 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Test\sthe\sresult\sof\spthread_create()\sand\sdo\snot\scall\spthread_join()\sif\sthe\nthread\screation\sfailed.\s\sTicket\s#3933.\s(CVS\s6839)
-D 2009-07-03T12:57:58
+C Make\sexplicit\sthe\srestrictions\son\sUPDATE,\sDELETE,\sand\sINSERT\sstatement\ssyntax\nwithin\striggers.\s\sTicket\s#3947.\s(CVS\s6840)
+D 2009-07-03T15:37:28
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -148,7 +148,7 @@ F src/os_unix.c cdb2a08b9ce4aa13b3f7b91d4dd60fb48be9f56a
 F src/os_win.c 725c38a524d168ce280446ad8761d731bc516405
 F src/pager.c 04fdbede529dc9f933637301d789dc7354df6e49
 F src/pager.h 5aec418bf99f568b92ae82816a1463400513726d
-F src/parse.y c48ce2025d848bbd1995f811e74dced8ab30abe6
+F src/parse.y bcd46d43fbd23a22b8c020a3eb1806b794794ed5
 F src/pcache.c 395f752a13574120bd7513a400ba02a265aaa76d
 F src/pcache.h 9b927ccc5a538e31b4c3bc7eec4f976db42a1324
 F src/pcache1.c 97e7e8e6e34026fb43b47d08532b0c02e959c26c
@@ -162,7 +162,7 @@ F src/select.c 71748b8e244112cf73df9446c4246c192276c30d
 F src/shell.c db2643650b9268df89a4bedca3f1c6d9e786f1bb
 F src/sqlite.h.in ccc67f14d5661240d05eadb8ab308aa637b0630c
 F src/sqlite3ext.h 1db7d63ab5de4b3e6b83dd03d1a4e64fef6d2a17
-F src/sqliteInt.h 7f6ab3d1c8aaedc64dc046dc413d9bbe187adf00
+F src/sqliteInt.h 8460c998fff4834f875c32233a2d63004163cee9
 F src/sqliteLimit.h ffe93f5a0c4e7bd13e70cd7bf84cfb5c3465f45d
 F src/status.c 237b193efae0cf6ac3f0817a208de6c6c6ef6d76
 F src/table.c cc86ad3d6ad54df7c63a3e807b5783c90411a08d
@@ -663,7 +663,7 @@ F test/trace.test 19ffbc09885c3321d56358a5738feae8587fb377
 F test/trans.test d887cb07630dc39879a322d958ad8b006137485c
 F test/trans2.test d5337e61de45e66b1fcbf9db833fa8c82e624b22
 F test/trans3.test d728abaa318ca364dc370e06576aa7e5fbed7e97
-F test/trigger1.test 53342dfd582155a599518f1918fdc997e9413177
+F test/trigger1.test 4ecf469e6f46610e0864f52b29d0ea162a2767c1
 F test/trigger2.test 53cf2209f68eb5bbb0ea0a07d694007fa702f1ed
 F test/trigger3.test 501b8489eb6b9cb5b005f60b071583c01a3c3041
 F test/trigger4.test 8e90ee98cba940cd5f96493f82e55083806ab8a0
@@ -739,7 +739,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 45fd5419a7cde29eb6ab5d98141bd642af0d78fb
-R 091f332adcee32735e6b502032b7718f
+P 304c5110ad958b2cc1ddff30e68c8791109128b5
+R 23c00185520dd16e8ecfdeb38c15386d
 U drh
-Z 92c87878b82808eaaf54bc37c5295c2b
+Z eccd19ba4bfa8e991ddfacf0b5d84154
diff --git a/manifest.uuid b/manifest.uuid
index 92301b8f00..310e79a646 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-304c5110ad958b2cc1ddff30e68c8791109128b5
\ No newline at end of file
+c8bf40df7be728b11bb633516d1988c6064a9d70
\ No newline at end of file
diff --git a/src/parse.y b/src/parse.y
index 25207cfc38..04d7acae5b 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -14,7 +14,7 @@
 ** the parser.  Lemon will also generate a header file containing
 ** numeric codes for all of the tokens.
 **
-** @(#) $Id: parse.y,v 1.284 2009/07/01 14:56:40 danielk1977 Exp $
+** @(#) $Id: parse.y,v 1.285 2009/07/03 15:37:28 drh Exp $
 */
 
 // All token codes are small integers with #defines that begin with "TK_"
@@ -1179,22 +1179,54 @@ trigger_cmd_list(A) ::= trigger_cmd(X) SEMI. {
   A = X;
 }
 
+// Disallow qualified table names on INSERT, UPDATE, and DELETE statements
+// within a trigger.  The table to INSERT, UPDATE, or DELETE is always in 
+// the same database as the table that the trigger fires on.
+//
+%type trnm {Token}
+trnm(A) ::= nm(X).   {A = X;}
+trnm(A) ::= nm DOT nm(X). {
+  A = X;
+  sqlite3ErrorMsg(pParse, 
+        "qualified table names are not allowed on INSERT, UPDATE, and DELETE "
+        "statements within triggers");
+}
+
+// Disallow the INDEX BY and NOT INDEXED clauses on UPDATE and DELETE
+// statements within triggers.  We make a specific error message for this
+// since it is an exception to the default grammar rules.
+//
+tridxby ::= .
+tridxby ::= INDEXED BY nm. {
+  sqlite3ErrorMsg(pParse,
+        "the INDEXED BY clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
+tridxby ::= NOT INDEXED. {
+  sqlite3ErrorMsg(pParse,
+        "the NOT INDEXED clause is not allowed on UPDATE or DELETE statements "
+        "within triggers");
+}
+
+
+
 %type trigger_cmd {TriggerStep*}
 %destructor trigger_cmd {sqlite3DeleteTriggerStep(pParse->db, $$);}
 // UPDATE 
-trigger_cmd(A) ::= UPDATE orconf(R) nm(X) SET setlist(Y) where_opt(Z).  
-               { A = sqlite3TriggerUpdateStep(pParse->db, &X, Y, Z, R); }
+trigger_cmd(A) ::=
+   UPDATE orconf(R) trnm(X) tridxby SET setlist(Y) where_opt(Z).  
+   { A = sqlite3TriggerUpdateStep(pParse->db, &X, Y, Z, R); }
 
 // INSERT
-trigger_cmd(A) ::= insert_cmd(R) INTO nm(X) inscollist_opt(F) 
-                   VALUES LP itemlist(Y) RP.  
-               {A = sqlite3TriggerInsertStep(pParse->db, &X, F, Y, 0, R);}
+trigger_cmd(A) ::=
+   insert_cmd(R) INTO trnm(X) inscollist_opt(F) VALUES LP itemlist(Y) RP.  
+   {A = sqlite3TriggerInsertStep(pParse->db, &X, F, Y, 0, R);}
 
-trigger_cmd(A) ::= insert_cmd(R) INTO nm(X) inscollist_opt(F) select(S).
+trigger_cmd(A) ::= insert_cmd(R) INTO trnm(X) inscollist_opt(F) select(S).
                {A = sqlite3TriggerInsertStep(pParse->db, &X, F, 0, S, R);}
 
 // DELETE
-trigger_cmd(A) ::= DELETE FROM nm(X) where_opt(Y).
+trigger_cmd(A) ::= DELETE FROM trnm(X) tridxby where_opt(Y).
                {A = sqlite3TriggerDeleteStep(pParse->db, &X, Y);}
 
 // SELECT
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 80510da2e3..304697e51f 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -11,7 +11,7 @@
 *************************************************************************
 ** Internal interface definitions for SQLite.
 **
-** @(#) $Id: sqliteInt.h,v 1.890 2009/06/26 15:14:55 drh Exp $
+** @(#) $Id: sqliteInt.h,v 1.891 2009/07/03 15:37:28 drh Exp $
 */
 #ifndef _SQLITEINT_H_
 #define _SQLITEINT_H_
@@ -2141,17 +2141,14 @@ struct Trigger {
  * 
  */
 struct TriggerStep {
-  int op;              /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
-  int orconf;          /* OE_Rollback etc. */
+  u8 op;               /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
+  u8 orconf;           /* OE_Rollback etc. */
   Trigger *pTrig;      /* The trigger that this step is a part of */
-
-  Select *pSelect;     /* Valid for SELECT and sometimes 
-                          INSERT steps (when pExprList == 0) */
-  Token target;        /* Target table for DELETE, UPDATE, INSERT.  Quoted */
-  Expr *pWhere;        /* Valid for DELETE, UPDATE steps */
-  ExprList *pExprList; /* Valid for UPDATE statements and sometimes 
-                           INSERT steps (when pSelect == 0)         */
-  IdList *pIdList;     /* Valid for INSERT statements only */
+  Select *pSelect;     /* SELECT statment or RHS of INSERT INTO .. SELECT ... */
+  Token target;        /* Target table for DELETE, UPDATE, INSERT */
+  Expr *pWhere;        /* The WHERE clause for DELETE or UPDATE steps */
+  ExprList *pExprList; /* SET clause for UPDATE.  VALUES clause for INSERT */
+  IdList *pIdList;     /* Column names for INSERT */
   TriggerStep *pNext;  /* Next in the link-list */
   TriggerStep *pLast;  /* Last element in link-list. Valid for 1st elem only */
 };
diff --git a/test/trigger1.test b/test/trigger1.test
index 18271e4270..b344beecce 100644
--- a/test/trigger1.test
+++ b/test/trigger1.test
@@ -639,4 +639,64 @@ do_test trigger1-15.2 {
   catchsql { INSERT INTO tA VALUES('abc', 2, 3) }
 } {1 {datatype mismatch}}
 
+# Ticket #3947:  Do not allow qualified table names on INSERT, UPDATE, and
+# DELETE statements within triggers.  Actually, this has never been allowed
+# by the grammar.  But the error message is confusing: one simply gets a
+# "syntax error".  That has now been changed to give a full error message.
+#
+do_test trigger1-16.1 {
+  db eval {
+    CREATE TABLE t16(a,b,c);
+    CREATE INDEX t16a ON t16(a);
+    CREATE INDEX t16b ON t16(b);
+  }
+  catchsql {
+    CREATE TRIGGER main.t16err1 AFTER INSERT ON tA BEGIN
+      INSERT INTO main.t16 VALUES(1,2,3);
+    END;
+  }
+} {1 {qualified table names are not allowed on INSERT, UPDATE, and DELETE statements within triggers}}
+do_test trigger1-16.2 {
+  catchsql {
+    CREATE TRIGGER main.t16err2 AFTER INSERT ON tA BEGIN
+      UPDATE main.t16 SET rowid=rowid+1;
+    END;
+  }
+} {1 {qualified table names are not allowed on INSERT, UPDATE, and DELETE statements within triggers}}
+do_test trigger1-16.3 {
+  catchsql {
+    CREATE TRIGGER main.t16err3 AFTER INSERT ON tA BEGIN
+      DELETE FROM main.t16;
+    END;
+  }
+} {1 {qualified table names are not allowed on INSERT, UPDATE, and DELETE statements within triggers}}
+do_test trigger1-16.4 {
+  catchsql {
+    CREATE TRIGGER main.t16err4 AFTER INSERT ON tA BEGIN
+      UPDATE t16 NOT INDEXED SET rowid=rowid+1;
+    END;
+  }
+} {1 {the NOT INDEXED clause is not allowed on UPDATE or DELETE statements within triggers}}
+do_test trigger1-16.5 {
+  catchsql {
+    CREATE TRIGGER main.t16err5 AFTER INSERT ON tA BEGIN
+      UPDATE t16 INDEXED BY t16a SET rowid=rowid+1 WHERE a=1;
+    END;
+  }
+} {1 {the INDEXED BY clause is not allowed on UPDATE or DELETE statements within triggers}}
+do_test trigger1-16.6 {
+  catchsql {
+    CREATE TRIGGER main.t16err6 AFTER INSERT ON tA BEGIN
+      DELETE FROM t16 NOT INDEXED WHERE a=123;
+    END;
+  }
+} {1 {the NOT INDEXED clause is not allowed on UPDATE or DELETE statements within triggers}}
+do_test trigger1-16.7 {
+  catchsql {
+    CREATE TRIGGER main.t16err7 AFTER INSERT ON tA BEGIN
+      DELETE FROM t16 INDEXED BY t16a WHERE a=123;
+    END;
+  }
+} {1 {the INDEXED BY clause is not allowed on UPDATE or DELETE statements within triggers}}
+
 finish_test