DROP IF EXISTS for ROLE/USER/GROUP

doc/src/sgml/ref/drop_group.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/drop_group.sgml,v 1.11 2005/07/26 23:24:02 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/drop_group.sgml,v 1.12 2006/02/04 19:06:46 adunstan Exp $
 PostgreSQL documentation
 -->
 
@@ -20,7 +20,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-DROP GROUP <replaceable class="PARAMETER">name</replaceable> [, ...]
+DROP GROUP [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [, ...]
 </synopsis>
  </refsynopsisdiv>
 

doc/src/sgml/ref/drop_role.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/drop_role.sgml,v 1.1 2005/07/26 23:24:02 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/drop_role.sgml,v 1.2 2006/02/04 19:06:46 adunstan Exp $
 PostgreSQL documentation
 -->
 
@@ -20,7 +20,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-DROP ROLE <replaceable class="PARAMETER">name</replaceable> [, ...]
+DROP ROLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [, ...]
 </synopsis>
  </refsynopsisdiv>
 
@@ -52,6 +52,17 @@ DROP ROLE <replaceable class="PARAMETER">name</replaceable> [, ...]
  <refsect1>
   <title>Parameters</title>
 
+  <variablelist>
+   <varlistentry>
+    <term><literal>IF EXISTS</literal></term>
+    <listitem>
+     <para>
+      Do not throw an error if the role does not exist. A notice is issued 
+      in this case.
+     </para>
+    </listitem>
+   </varlistentry>
+
   <variablelist>
    <varlistentry>
     <term><replaceable class="PARAMETER">name</replaceable></term>

doc/src/sgml/ref/drop_user.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/drop_user.sgml,v 1.21 2005/07/26 23:24:02 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/drop_user.sgml,v 1.22 2006/02/04 19:06:46 adunstan Exp $
 PostgreSQL documentation
 -->
 
@@ -20,7 +20,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-DROP USER <replaceable class="PARAMETER">name</replaceable> [, ...]
+DROP USER [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [, ...]
 </synopsis>
  </refsynopsisdiv>
 

src/backend/commands/user.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/commands/user.c,v 1.167 2005/12/23 16:46:39 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/user.c,v 1.168 2006/02/04 19:06:46 adunstan Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -840,9 +840,22 @@ DropRole(DropRoleStmt *stmt)
 							   PointerGetDatum(role),
 							   0, 0, 0);
 		if (!HeapTupleIsValid(tuple))
-			ereport(ERROR,
+		{
-					(errcode(ERRCODE_UNDEFINED_OBJECT),
+			if (!stmt->missing_ok)
-					 errmsg("role \"%s\" does not exist", role)));
+			{
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_OBJECT),
+						 errmsg("role \"%s\" does not exist", role)));
+			}
+			else
+			{
+				ereport(NOTICE,
+						(errmsg("role \"%s\" does not exist, skipping", 
+								role)));
+			}
+
+			continue;
+		}
 
 		roleid = HeapTupleGetOid(tuple);
 

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.325 2006/01/31 21:39:23 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.326 2006/02/04 19:06:46 adunstan Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2518,6 +2518,7 @@ _copyDropRoleStmt(DropRoleStmt *from)
 	DropRoleStmt *newnode = makeNode(DropRoleStmt);
 
 	COPY_NODE_FIELD(roles);
+	COPY_SCALAR_FIELD(missing_ok);
 
 	return newnode;
 }

src/backend/nodes/equalfuncs.c

@@ -18,7 +18,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.261 2006/01/31 21:39:23 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.262 2006/02/04 19:06:46 adunstan Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1398,6 +1398,7 @@ static bool
 _equalDropRoleStmt(DropRoleStmt *a, DropRoleStmt *b)
 {
 	COMPARE_NODE_FIELD(roles);
+	COMPARE_SCALAR_FIELD(missing_ok);
 
 	return true;
 }

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.525 2006/01/31 22:40:03 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.526 2006/02/04 19:06:46 adunstan Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -824,9 +824,17 @@ DropRoleStmt:
 			DROP ROLE name_list
 				{
 					DropRoleStmt *n = makeNode(DropRoleStmt);
+					n->missing_ok = FALSE;
 					n->roles = $3;
 					$$ = (Node *)n;
 				}
+			| DROP ROLE IF_P EXISTS name_list
+				{
+					DropRoleStmt *n = makeNode(DropRoleStmt);
+					n->missing_ok = TRUE;
+					n->roles = $5;
+					$$ = (Node *)n;
+				}
 			;
 
 /*****************************************************************************
@@ -842,9 +850,17 @@ DropUserStmt:
 			DROP USER name_list
 				{
 					DropRoleStmt *n = makeNode(DropRoleStmt);
+					n->missing_ok = FALSE;
 					n->roles = $3;
 					$$ = (Node *)n;
 				}
+			| DROP USER IF_P EXISTS name_list
+				{
+					DropRoleStmt *n = makeNode(DropRoleStmt);
+					n->roles = $5;
+					n->missing_ok = TRUE;
+					$$ = (Node *)n;
+				}
 			;
 
 
@@ -900,9 +916,17 @@ DropGroupStmt:
 			DROP GROUP_P name_list
 				{
 					DropRoleStmt *n = makeNode(DropRoleStmt);
+					n->missing_ok = FALSE;
 					n->roles = $3;
 					$$ = (Node *)n;
 				}
+			| DROP GROUP_P IF_P EXISTS name_list
+				{
+					DropRoleStmt *n = makeNode(DropRoleStmt);
+					n->missing_ok = TRUE;
+					n->roles = $5;
+					$$ = (Node *)n;
+				}
 		;
 
 

src/include/nodes/parsenodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.299 2006/01/21 02:16:20 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.300 2006/02/04 19:06:46 adunstan Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1193,6 +1193,7 @@ typedef struct DropRoleStmt
 {
 	NodeTag		type;
 	List	   *roles;			/* List of roles to remove */
+	bool		missing_ok;		/* skip error if a role is missing? */
 } DropRoleStmt;
 
 /* ----------------------

src/test/regress/expected/drop_if_exists.out

@@ -65,3 +65,27 @@ ERROR:  type "test_domain_exists" does not exist
 DROP TABLE IF EXISTS test_exists;
 DROP TABLE test_exists;
 ERROR:  table "test_exists" does not exist
+---
+--- role/user/group
+---
+CREATE USER tu1;
+CREATE ROLE tr1;
+CREATE GROUP tg1;
+DROP USER tu2;
+ERROR:  role "tu2" does not exist
+DROP USER IF EXISTS tu1, tu2;
+NOTICE:  role "tu2" does not exist, skipping
+DROP USER tu1;
+ERROR:  role "tu1" does not exist
+DROP ROLE tr2;
+ERROR:  role "tr2" does not exist
+DROP ROLE IF EXISTS tr1, tr2;
+NOTICE:  role "tr2" does not exist, skipping
+DROP ROLE tr1;
+ERROR:  role "tr1" does not exist
+DROP GROUP tg2;
+ERROR:  role "tg2" does not exist
+DROP GROUP IF EXISTS tg1, tg2;
+NOTICE:  role "tg2" does not exist, skipping
+DROP GROUP tg1;
+ERROR:  role "tg1" does not exist

src/test/regress/sql/drop_if_exists.sql

@@ -89,3 +89,30 @@ DROP TABLE IF EXISTS test_exists;
 
 DROP TABLE test_exists;
 
+
+---
+--- role/user/group
+---
+
+CREATE USER tu1;
+CREATE ROLE tr1;
+CREATE GROUP tg1;
+
+DROP USER tu2;
+
+DROP USER IF EXISTS tu1, tu2;
+
+DROP USER tu1;
+
+DROP ROLE tr2;
+
+DROP ROLE IF EXISTS tr1, tr2;
+
+DROP ROLE tr1;
+
+DROP GROUP tg2;
+
+DROP GROUP IF EXISTS tg1, tg2;
+
+DROP GROUP tg1;
+