Allow an optional alias for the target table to be specified for UPDATE

and DELETE. If specified, the alias must be used instead of the full
table name. Also, the alias currently cannot be used in the SET clause
of UPDATE.

Patch from Atsushi Ogawa, various editorialization by Neil Conway.
Along the way, make the rowtypes regression test pass if add_missing_from
is enabled, and add a new (skeletal) regression test for DELETE.

diff --git a/doc/src/sgml/ref/delete.sgml b/doc/src/sgml/ref/delete.sgml
index 8369d9913725bd0bcd652ff3be3845449e9aa48f..b61e6cacd2132d3544eaef490a168a9209dcaa45 100644 (file)
--- a/doc/src/sgml/ref/delete.sgml
+++ b/doc/src/sgml/ref/delete.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/delete.sgml,v 1.25 2005/11/01 21:09:50 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/delete.sgml,v 1.26 2006/01/22 05:20:33 neilc Exp $
 PostgreSQL documentation
 -->
 
@@ -20,7 +20,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-DELETE FROM [ ONLY ] <replaceable class="PARAMETER">table</replaceable>
+DELETE FROM [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ [ AS ] <replaceable class="parameter">alias</replaceable> ]
     [ USING <replaceable class="PARAMETER">usinglist</replaceable> ]
     [ WHERE <replaceable class="PARAMETER">condition</replaceable> ]
 </synopsis>
@@ -91,6 +91,19 @@ DELETE FROM [ ONLY ] <replaceable class="PARAMETER">table</replaceable>
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><replaceable class="parameter">alias</replaceable></term>
+    <listitem>
+     <para>
+      A substitute name for the target table. When an alias is
+      provided, it completely hides the actual name of the table.  For
+      example, given <literal>DELETE FROM foo AS f</>, the remainder
+      of the <command>DELETE</command> statement must refer to this
+      table as <literal>f</> not <literal>foo</>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><replaceable class="PARAMETER">usinglist</replaceable></term>
     <listitem>

diff --git a/doc/src/sgml/ref/update.sgml b/doc/src/sgml/ref/update.sgml
index 503f41de12bcc6e7141126751158cf5eac0de013..95e4310ab424657a2c175b62a38d1d3b96c95ea4 100644 (file)
--- a/doc/src/sgml/ref/update.sgml
+++ b/doc/src/sgml/ref/update.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.34 2006/01/19 23:09:42 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.35 2006/01/22 05:20:33 neilc Exp $
 PostgreSQL documentation
 -->
 
@@ -20,7 +20,8 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-UPDATE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> SET <replaceable class="PARAMETER">column</replaceable> = { <replaceable class="PARAMETER">expression</replaceable> | DEFAULT } [, ...]
+UPDATE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ [ AS ] <replaceable class="parameter">alias</replaceable> ]
+    SET <replaceable class="PARAMETER">column</replaceable> = { <replaceable class="PARAMETER">expression</replaceable> | DEFAULT } [, ...]
     [ FROM <replaceable class="PARAMETER">fromlist</replaceable> ]
     [ WHERE <replaceable class="PARAMETER">condition</replaceable> ]
 </synopsis>
@@ -73,6 +74,21 @@ UPDATE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> SET <replacea
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><replaceable class="parameter">alias</replaceable></term>
+    <listitem>
+     <para>
+      A substitute name for the target table. When an alias is
+      provided, it completely hides the actual name of the table.  For
+      example, given <literal>UPDATE foo AS f</>, the remainder of the
+      <command>UPDATE</command> statement must refer to this table as
+      <literal>f</> not <literal>foo</>. You cannot use the alias in
+      the <literal>SET</literal> clause.  For example, <literal>SET
+      f.col = 1</> is invalid.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><replaceable class="PARAMETER">column</replaceable></term>
     <listitem>

diff --git a/doc/src/sgml/regress.sgml b/doc/src/sgml/regress.sgml
index 05749a3157bcc8cba87e3b334b9d9a88b3c59cf7..11f9468860fbaaa08cec328cd945c454b10adb40 100644 (file)
--- a/doc/src/sgml/regress.sgml
+++ b/doc/src/sgml/regress.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/regress.sgml,v 1.49 2005/10/18 21:43:33 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/regress.sgml,v 1.50 2006/01/22 05:20:32 neilc Exp $ -->
 
  <chapter id="regress">
   <title id="regress-title">Regression Tests</title>
@@ -49,7 +49,7 @@ gmake check
 <screen>
 <computeroutput>
 ======================
- All 98 tests passed.
+ All 100 tests passed.
 ======================
 </computeroutput>
 </screen>

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 41b22d811c9868c457ee855209b021f9315191e3..22e20165b96aec1d3e3e71b4c9aff2c55ab62a49 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.522 2006/01/21 02:16:19 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.523 2006/01/22 05:20:33 neilc Exp $
  *
  * HISTORY
  *       AUTHOR                        DATE                    MAJOR EVENT
@@ -291,6 +291,7 @@ static void doNegateFloat(Value *v);
 %type <node>   table_ref
 %type <jexpr>  joined_table
 %type <range>  relation_expr
+%type <range>  relation_expr_opt_alias
 %type <target> target_el insert_target_el update_target_el insert_column_item
 
 %type <typnam> Typename SimpleTypename ConstTypename
@@ -5148,7 +5149,8 @@ insert_column_item:
  *
  *****************************************************************************/
 
-DeleteStmt: DELETE_P FROM relation_expr using_clause where_clause
+DeleteStmt: DELETE_P FROM relation_expr_opt_alias
+                       using_clause where_clause
                                {
                                        DeleteStmt *n = makeNode(DeleteStmt);
                                        n->relation = $3;
@@ -5200,7 +5202,7 @@ opt_nowait:       NOWAIT                                                  { $$ = TRUE; }
  *
  *****************************************************************************/
 
-UpdateStmt: UPDATE relation_expr
+UpdateStmt: UPDATE relation_expr_opt_alias
                        SET update_target_list
                        from_clause
                        where_clause
@@ -5878,6 +5880,20 @@ relation_expr:
                ;
 
 
+relation_expr_opt_alias: relation_expr
+                               {
+                                       $$ = $1;
+                               }
+                       | relation_expr opt_as IDENT
+                               {
+                                       Alias *alias = makeNode(Alias);
+                                       alias->aliasname = $3;
+                                       $1->alias = alias;
+                                       $$ = $1;
+                               }
+               ;
+
+
 func_table: func_expr                                                          { $$ = $1; }
                ;
 

diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index aee45f3d2050ee447297f48dc786149e1c466ba1..934802e16ec7986844c553b4d92b4e61c18833d6 100644 (file)
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.144 2005/11/22 18:17:16 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.145 2006/01/22 05:20:34 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -160,7 +160,7 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
         * Now build an RTE.
         */
        rte = addRangeTableEntryForRelation(pstate, pstate->p_target_relation,
-                                                                               NULL, inh, false);
+                                                                               relation->alias, inh, false);
        pstate->p_target_rangetblentry = rte;
 
        /* assume new rte is at end */

diff --git a/src/test/regress/expected/delete.out b/src/test/regress/expected/delete.out
new file mode 100644 (file)
index 0000000..68128f6
--- /dev/null
+++ b/src/test/regress/expected/delete.out
@@ -0,0 +1,27 @@
+CREATE TABLE delete_test (
+    id SERIAL PRIMARY KEY,
+    a INT
+);
+NOTICE:  CREATE TABLE will create implicit sequence "delete_test_id_seq" for serial column "delete_test.id"
+NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "delete_test_pkey" for table "delete_test"
+INSERT INTO delete_test (a) VALUES (10);
+INSERT INTO delete_test (a) VALUES (50);
+INSERT INTO delete_test (a) VALUES (100);
+-- allow an alias to be specified for DELETE's target table
+DELETE FROM delete_test AS dt WHERE dt.a > 75;
+-- if an alias is specified, don't allow the original table name
+-- to be referenced
+BEGIN;
+SET LOCAL add_missing_from = false;
+DELETE FROM delete_test dt WHERE delete_test.a > 25;
+ERROR:  invalid reference to FROM-clause entry for table "delete_test"
+HINT:  Perhaps you meant to reference the table alias "dt".
+ROLLBACK;
+SELECT * FROM delete_test;
+ id | a  
+----+----
+  1 | 10
+  2 | 50
+(2 rows)
+
+DROP TABLE delete_test;

diff --git a/src/test/regress/expected/rowtypes.out b/src/test/regress/expected/rowtypes.out
index fc46dd14e19007b6acf7d027eade73c80fc2b807..c6b1bfac3982e1276ff9f6ba66cf305ddef8b5fe 100644 (file)
--- a/src/test/regress/expected/rowtypes.out
+++ b/src/test/regress/expected/rowtypes.out
@@ -59,8 +59,11 @@ select * from quadtable;
   2 | ("(,4.4)","(5.5,6.6)")
 (2 rows)
 
+begin;
+set local add_missing_from = false;
 select f1, q.c1 from quadtable;                -- fails, q is a table reference
 ERROR:  missing FROM-clause entry for table "q"
+rollback;
 select f1, (q).c1, (qq.q).c1.i from quadtable qq;
  f1 |    c1     |  i  
 ----+-----------+-----

diff --git a/src/test/regress/expected/update.out b/src/test/regress/expected/update.out
index 3fca2fb41ac71c0cea4ddbf35d13026fa46a34ff..1ff7c8918f5184e6c7154ac2ec49a7f9055ecaa3 100644 (file)
--- a/src/test/regress/expected/update.out
+++ b/src/test/regress/expected/update.out
@@ -22,4 +22,29 @@ SELECT * FROM update_test;
  10 |  
 (2 rows)
 
+-- aliases for the UPDATE target table
+UPDATE update_test AS t SET b = 10 WHERE t.a = 10;
+SELECT * FROM update_test;
+ a  | b  
+----+----
+ 10 | 10
+ 10 | 10
+(2 rows)
+
+UPDATE update_test t SET b = t.b + 10 WHERE t.a = 10;
+SELECT * FROM update_test;
+ a  | b  
+----+----
+ 10 | 20
+ 10 | 20
+(2 rows)
+
+-- if an alias for the target table is specified, don't allow references
+-- to the original table name
+BEGIN;
+SET LOCAL add_missing_from = false;
+UPDATE update_test AS t SET b = update_test.b + 10 WHERE t.a = 10;
+ERROR:  invalid reference to FROM-clause entry for table "update_test"
+HINT:  Perhaps you meant to reference the table alias "t".
+ROLLBACK;
 DROP TABLE update_test;

diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d5777794bfbc047f89db676829a5f69ba11e02bf..fef609711b2df346269e3f56286733eeca3a99b2 100644 (file)
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -60,7 +60,7 @@ ignore: random
 # ----------
 # The fourth group of parallel test
 # ----------
-test: select_into select_distinct select_distinct_on select_implicit select_having subselect union case join aggregates transactions random portals arrays btree_index hash_index update namespace prepared_xacts
+test: select_into select_distinct select_distinct_on select_implicit select_having subselect union case join aggregates transactions random portals arrays btree_index hash_index update namespace prepared_xacts delete
 
 test: privileges
 test: misc

diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule
index dd60070433c9b1f3fb75d9bc2f273602bb2fc9ee..3342dc2ba1fe03c4336333609b9c78cbcaa94001 100644 (file)
--- a/src/test/regress/serial_schedule
+++ b/src/test/regress/serial_schedule
@@ -1,4 +1,4 @@
-# $PostgreSQL: pgsql/src/test/regress/serial_schedule,v 1.29 2005/11/19 17:39:45 adunstan Exp $
+# $PostgreSQL: pgsql/src/test/regress/serial_schedule,v 1.30 2006/01/22 05:20:34 neilc Exp $
 # This should probably be in an order similar to parallel_schedule.
 test: boolean
 test: char
@@ -74,6 +74,7 @@ test: arrays
 test: btree_index
 test: hash_index
 test: update
+test: delete
 test: namespace
 test: prepared_xacts
 test: privileges

diff --git a/src/test/regress/sql/delete.sql b/src/test/regress/sql/delete.sql
new file mode 100644 (file)
index 0000000..86cabfc
--- /dev/null
+++ b/src/test/regress/sql/delete.sql
@@ -0,0 +1,22 @@
+CREATE TABLE delete_test (
+    id SERIAL PRIMARY KEY,
+    a INT
+);
+
+INSERT INTO delete_test (a) VALUES (10);
+INSERT INTO delete_test (a) VALUES (50);
+INSERT INTO delete_test (a) VALUES (100);
+
+-- allow an alias to be specified for DELETE's target table
+DELETE FROM delete_test AS dt WHERE dt.a > 75;
+
+-- if an alias is specified, don't allow the original table name
+-- to be referenced
+BEGIN;
+SET LOCAL add_missing_from = false;
+DELETE FROM delete_test dt WHERE delete_test.a > 25;
+ROLLBACK;
+
+SELECT * FROM delete_test;
+
+DROP TABLE delete_test;
\ No newline at end of file

diff --git a/src/test/regress/sql/rowtypes.sql b/src/test/regress/sql/rowtypes.sql
index 613c4e91f9180c84f516bab122ca3661e462647e..43d57bc60355b2af68ed0c611a14fc814e33a84f 100644 (file)
--- a/src/test/regress/sql/rowtypes.sql
+++ b/src/test/regress/sql/rowtypes.sql
@@ -35,7 +35,10 @@ insert into quadtable values (2, ((null,4.4),(5.5,6.6)));
 
 select * from quadtable;
 
+begin;
+set local add_missing_from = false;
 select f1, q.c1 from quadtable;                -- fails, q is a table reference
+rollback;
 
 select f1, (q).c1, (qq.q).c1.i from quadtable qq;
 

diff --git a/src/test/regress/sql/update.sql b/src/test/regress/sql/update.sql
index 577596abb1b75432247f6d3d1c2bcdc54c776d34..99fd74bca79d2569fd86d11adc5c0a84763cbef2 100644 (file)
--- a/src/test/regress/sql/update.sql
+++ b/src/test/regress/sql/update.sql
@@ -16,4 +16,20 @@ UPDATE update_test SET a = DEFAULT, b = DEFAULT;
 
 SELECT * FROM update_test;
 
+-- aliases for the UPDATE target table
+UPDATE update_test AS t SET b = 10 WHERE t.a = 10;
+
+SELECT * FROM update_test;
+
+UPDATE update_test t SET b = t.b + 10 WHERE t.a = 10;
+
+SELECT * FROM update_test;
+
+-- if an alias for the target table is specified, don't allow references
+-- to the original table name
+BEGIN;
+SET LOCAL add_missing_from = false;
+UPDATE update_test AS t SET b = update_test.b + 10 WHERE t.a = 10;
+ROLLBACK;
+
 DROP TABLE update_test;