From 8e68d783902b0b47f377efa4a23a04ddeef272a8 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 28 Feb 2006 22:37:27 +0000
Subject: Allow the syntax CREATE TYPE foo, with no parameters, to permit
 explicit creation of a shell type.  This allows a less hacky way of dealing
 with the mutual dependency between a datatype and its I/O functions: make a
 shell type, then make the functions, then define the datatype fully. We
 should fix pg_dump to handle things this way, but this commit just deals with
 the backend.

Martijn van Oosterhout, with some corrections by Tom Lane.
---
 src/backend/commands/typecmds.c | 49 +++++++++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 17 deletions(-)

(limited to 'src/backend/commands/typecmds.c')

diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 143695252f4..f8e1a2665cf 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.86 2006/01/13 18:06:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.87 2006/02/28 22:37:26 tgl Exp $
  *
  * DESCRIPTION
  *	  The "DefineFoo" routines take the parse tree and pick out the
@@ -138,6 +138,37 @@ DefineType(List *names, List *parameters)
 				 errmsg("type names must be %d characters or less",
 						NAMEDATALEN - 2)));
 
+	/*
+	 * Look to see if type already exists (presumably as a shell; if not,
+	 * TypeCreate will complain).  If it doesn't, create it as a shell, so
+	 * that the OID is known for use in the I/O function definitions.
+	 */
+	typoid = GetSysCacheOid(TYPENAMENSP,
+							CStringGetDatum(typeName),
+							ObjectIdGetDatum(typeNamespace),
+							0, 0);
+	if (!OidIsValid(typoid))
+	{
+		typoid = TypeShellMake(typeName, typeNamespace);
+		/* Make new shell type visible for modification below */
+		CommandCounterIncrement();
+
+		/*
+		 * If the command was a parameterless CREATE TYPE, we're done ---
+		 * creating the shell type was all we're supposed to do.
+		 */
+		if (parameters == NIL)
+			return;
+	}
+	else
+	{
+		/* Complain if dummy CREATE TYPE and entry already exists */
+		if (parameters == NIL)
+			ereport(ERROR,
+					(errcode(ERRCODE_DUPLICATE_OBJECT),
+					 errmsg("type \"%s\" already exists", typeName)));
+	}
+
 	foreach(pl, parameters)
 	{
 		DefElem    *defel = (DefElem *) lfirst(pl);
@@ -240,22 +271,6 @@ DefineType(List *names, List *parameters)
 				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 				 errmsg("type output function must be specified")));
 
-	/*
-	 * Look to see if type already exists (presumably as a shell; if not,
-	 * TypeCreate will complain).  If it doesn't, create it as a shell, so
-	 * that the OID is known for use in the I/O function definitions.
-	 */
-	typoid = GetSysCacheOid(TYPENAMENSP,
-							CStringGetDatum(typeName),
-							ObjectIdGetDatum(typeNamespace),
-							0, 0);
-	if (!OidIsValid(typoid))
-	{
-		typoid = TypeShellMake(typeName, typeNamespace);
-		/* Make new shell type visible for modification below */
-		CommandCounterIncrement();
-	}
-
 	/*
 	 * Convert I/O proc names to OIDs
 	 */
-- 
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