Fix a bunch of problems with domains by making them use special input functions

that apply the necessary domain constraint checks immediately.  This fixes
cases where domain constraints went unchecked for statement parameters,
PL function local variables and results, etc.  We can also eliminate existing
special cases for domains in places that had gotten it right, eg COPY.

Also, allow domains over domains (base of a domain is another domain type).
This almost worked before, but was disallowed because the original patch
hadn't gotten it quite right.

Author: tglsfdc

doc/src/sgml/ref/create_domain.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.27 2005/12/25 01:41:15 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.28 2006/04/05 22:11:54 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -35,8 +35,10 @@ where <replaceable class="PARAMETER">constraint</replaceable> is:
   <title>Description</title>
 
   <para>
-   <command>CREATE DOMAIN</command> creates a new data domain.  The
-   user who defines a domain becomes its owner.
+   <command>CREATE DOMAIN</command> creates a new domain.  A domain is
+   essentially a data type with optional constraints (restrictions on
+   the allowed set of values).
+   The user who defines a domain becomes its owner.
   </para>
 
   <para>
@@ -48,24 +50,13 @@ where <replaceable class="PARAMETER">constraint</replaceable> is:
   </para>
 
   <para>
-   Domains are useful for abstracting common fields between tables
-   into a single location for maintenance.  For example, an email address
-   column may be used in several tables, all with the same properties.
-   Define a domain and use that rather than setting up each table's
-   constraints individually. 
+   Domains are useful for abstracting common constraints on fields into
+   a single location for maintenance.  For example, several tables might
+   contain email address columns, all requiring the same CHECK constraint
+   to verify the address syntax.
+   Define a domain rather than setting up each table's constraint
+   individually.
   </para>
-
-  <caution>
-  <para>
-   At present, declaring a function result value as a domain 
-   is pretty dangerous, because none of the procedural languages enforce domain constraints 
-   on their results.  You'll need to make sure that the function code itself
-   respects the constraints.  In <application>PL/pgSQL</>, one possible
-   workaround is to explicitly cast the result value to the domain type
-   when you return it.  <application>PL/pgSQL</> does not enforce domain
-   constraints for local variables within functions, either.
-  </para>
-  </caution>
  </refsect1>
 
  <refsect1>
@@ -156,7 +147,7 @@ where <replaceable class="PARAMETER">constraint</replaceable> is:
       <literal>CHECK</> clauses specify integrity constraints or tests
       which values of the domain must satisfy.
       Each constraint must be an expression
-      producing a Boolean result.  It should use the name <literal>VALUE</>
+      producing a Boolean result.  It should use the key word <literal>VALUE</>
       to refer to the value being tested.
      </para>
 
@@ -185,12 +176,12 @@ OR VALUE ~ '^\\d{5}-\\d{4}$'
 );
 
 CREATE TABLE us_snail_addy (
-  address_id SERIAL PRIMARY KEY
-, street1 TEXT NOT NULL
-, street2 TEXT
-, street3 TEXT
-, city TEXT NOT NULL
-, postal us_postal_code NOT NULL
+  address_id SERIAL PRIMARY KEY,
+  street1 TEXT NOT NULL,
+  street2 TEXT,
+  street3 TEXT,
+  city TEXT NOT NULL,
+  postal us_postal_code NOT NULL
 );
 </programlisting>
   </para>

doc/src/sgml/ref/create_type.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.62 2006/04/04 19:35:32 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.63 2006/04/05 22:11:54 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -591,6 +591,7 @@ CREATE TABLE big_objs (
    <member><xref linkend="sql-createfunction" endterm="sql-createfunction-title"></member>
    <member><xref linkend="sql-droptype" endterm="sql-droptype-title"></member>
    <member><xref linkend="sql-altertype" endterm="sql-altertype-title"></member>
+   <member><xref linkend="sql-createdomain" endterm="sql-createdomain-title"></member>
   </simplelist>
  </refsect1>
 

src/backend/access/common/printtup.c

@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/common/printtup.c,v 1.95 2006/04/04 19:35:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/common/printtup.c,v 1.96 2006/04/05 22:11:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -177,7 +177,6 @@ SendRowDescriptionMessage(TupleDesc typeinfo, List *targetlist, int16 *formats)
 	{
 		Oid			atttypid = attrs[i]->atttypid;
 		int32		atttypmod = attrs[i]->atttypmod;
-		Oid			basetype;
 
 		pq_sendstring(&buf, NameStr(attrs[i]->attname));
 		/* column ID info appears in protocol 3.0 and up */
@@ -203,12 +202,7 @@ SendRowDescriptionMessage(TupleDesc typeinfo, List *targetlist, int16 *formats)
 			}
 		}
 		/* If column is a domain, send the base type and typmod instead */
-		basetype = getBaseType(atttypid);
-		if (basetype != atttypid)
-		{
-			atttypmod = get_typtypmod(atttypid);
-			atttypid = basetype;
-		}
+		atttypid = getBaseTypeAndTypmod(atttypid, &atttypmod);
 		pq_sendint(&buf, (int) atttypid, sizeof(atttypid));
 		pq_sendint(&buf, attrs[i]->attlen, sizeof(attrs[i]->attlen));
 		/* typmod appears in protocol 2.0 and up */

src/backend/commands/copy.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.262 2006/04/04 19:35:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.263 2006/04/05 22:11:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1545,9 +1545,7 @@ CopyFrom(CopyState cstate)
 	FmgrInfo	oid_in_function;
 	Oid		   *typioparams;
 	Oid			oid_typioparam;
-	ExprState **constraintexprs;
 	bool	   *force_notnull;
-	bool		hasConstraints = false;
 	int			attnum;
 	int			i;
 	Oid			in_func_oid;
@@ -1608,7 +1606,6 @@ CopyFrom(CopyState cstate)
 	typioparams = (Oid *) palloc(num_phys_attrs * sizeof(Oid));
 	defmap = (int *) palloc(num_phys_attrs * sizeof(int));
 	defexprs = (ExprState **) palloc(num_phys_attrs * sizeof(ExprState *));
-	constraintexprs = (ExprState **) palloc0(num_phys_attrs * sizeof(ExprState *));
 	force_notnull = (bool *) palloc(num_phys_attrs * sizeof(bool));
 
 	for (attnum = 1; attnum <= num_phys_attrs; attnum++)
@@ -1646,35 +1643,6 @@ CopyFrom(CopyState cstate)
 				num_defaults++;
 			}
 		}
-
-		/* If it's a domain type, set up to check domain constraints */
-		if (get_typtype(attr[attnum - 1]->atttypid) == 'd')
-		{
-			Param	   *prm;
-			Node	   *node;
-
-			/*
-			 * Easiest way to do this is to use parse_coerce.c to set up an
-			 * expression that checks the constraints.	(At present, the
-			 * expression might contain a length-coercion-function call and/or
-			 * CoerceToDomain nodes.)  The bottom of the expression is a Param
-			 * node so that we can fill in the actual datum during the data
-			 * input loop.
-			 */
-			prm = makeNode(Param);
-			prm->paramkind = PARAM_EXEC;
-			prm->paramid = 0;
-			prm->paramtype = getBaseType(attr[attnum - 1]->atttypid);
-
-			node = coerce_to_domain((Node *) prm,
-									prm->paramtype,
-									attr[attnum - 1]->atttypid,
-									COERCE_IMPLICIT_CAST, false, false);
-
-			constraintexprs[attnum - 1] = ExecPrepareExpr((Expr *) node,
-														  estate);
-			hasConstraints = true;
-		}
 	}
 
 	/* Prepare to catch AFTER triggers. */
@@ -1743,11 +1711,6 @@ CopyFrom(CopyState cstate)
 	nfields = file_has_oids ? (attr_count + 1) : attr_count;
 	field_strings = (char **) palloc(nfields * sizeof(char *));
 
-	/* Make room for a PARAM_EXEC value for domain constraint checks */
-	if (hasConstraints)
-		econtext->ecxt_param_exec_vals = (ParamExecData *)
-			palloc0(sizeof(ParamExecData));
-
 	/* Initialize state variables */
 	cstate->fe_eof = false;
 	cstate->eol_type = EOL_UNKNOWN;
@@ -1942,33 +1905,6 @@ CopyFrom(CopyState cstate)
 				nulls[defmap[i]] = ' ';
 		}
 
-		/* Next apply any domain constraints */
-		if (hasConstraints)
-		{
-			ParamExecData *prmdata = &econtext->ecxt_param_exec_vals[0];
-
-			for (i = 0; i < num_phys_attrs; i++)
-			{
-				ExprState  *exprstate = constraintexprs[i];
-
-				if (exprstate == NULL)
-					continue;	/* no constraint for this attr */
-
-				/* Insert current row's value into the Param value */
-				prmdata->value = values[i];
-				prmdata->isnull = (nulls[i] == 'n');
-
-				/*
-				 * Execute the constraint expression.  Allow the expression to
-				 * replace the value (consider e.g. a timestamp precision
-				 * restriction).
-				 */
-				values[i] = ExecEvalExpr(exprstate, econtext,
-										 &isnull, NULL);
-				nulls[i] = isnull ? 'n' : ' ';
-			}
-		}
-
 		/* And now we can form the input tuple. */
 		tuple = heap_formtuple(tupDesc, values, nulls);
 
@@ -2043,7 +1979,6 @@ CopyFrom(CopyState cstate)
 	pfree(typioparams);
 	pfree(defmap);
 	pfree(defexprs);
-	pfree(constraintexprs);
 	pfree(force_notnull);
 
 	ExecDropSingleTupleTableSlot(slot);

src/backend/commands/typecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.89 2006/03/14 22:48:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.90 2006/04/05 22:11:55 tgl Exp $
  *
  * DESCRIPTION
  *	  The "DefineFoo" routines take the parse tree and pick out the
@@ -536,6 +536,7 @@ DefineDomain(CreateDomainStmt *stmt)
 	Oid			sendProcedure;
 	Oid			analyzeProcedure;
 	bool		byValue;
+	Oid			typelem;
 	char		delimiter;
 	char		alignment;
 	char		storage;
@@ -547,7 +548,6 @@ DefineDomain(CreateDomainStmt *stmt)
 	char	   *defaultValueBin = NULL;
 	bool		typNotNull = false;
 	bool		nullDefined = false;
-	Oid			basetypelem;
 	int32		typNDims = list_length(stmt->typename->arrayBounds);
 	HeapTuple	typeTup;
 	List	   *schema = stmt->constraints;
@@ -589,12 +589,12 @@ DefineDomain(CreateDomainStmt *stmt)
 	basetypeoid = HeapTupleGetOid(typeTup);
 
 	/*
-	 * Base type must be a plain base type.  Domains over pseudo types would
-	 * create a security hole.	Domains of domains might be made to work in
-	 * the future, but not today.  Ditto for domains over complex types.
+	 * Base type must be a plain base type or another domain.  Domains over
+	 * pseudotypes would create a security hole.  Domains over composite
+	 * types might be made to work in the future, but not today.
 	 */
 	typtype = baseType->typtype;
-	if (typtype != 'b')
+	if (typtype != 'b' && typtype != 'd')
 		ereport(ERROR,
 				(errcode(ERRCODE_DATATYPE_MISMATCH),
 				 errmsg("\"%s\" is not a valid base type for a domain",
@@ -612,13 +612,16 @@ DefineDomain(CreateDomainStmt *stmt)
 	/* Storage Length */
 	internalLength = baseType->typlen;
 
+	/* Array element type (in case base type is an array) */
+	typelem = baseType->typelem;
+
 	/* Array element Delimiter */
 	delimiter = baseType->typdelim;
 
 	/* I/O Functions */
-	inputProcedure = baseType->typinput;
+	inputProcedure = F_DOMAIN_IN;
 	outputProcedure = baseType->typoutput;
-	receiveProcedure = baseType->typreceive;
+	receiveProcedure = F_DOMAIN_RECV;
 	sendProcedure = baseType->typsend;
 
 	/* Analysis function */
@@ -636,13 +639,6 @@ DefineDomain(CreateDomainStmt *stmt)
 	if (!isnull)
 		defaultValueBin = DatumGetCString(DirectFunctionCall1(textout, datum));
 
-	/*
-	 * Pull out the typelem name of the parent OID.
-	 *
-	 * This is what enables us to make a domain of an array
-	 */
-	basetypelem = baseType->typelem;
-
 	/*
 	 * Run through constraints manually to avoid the additional processing
 	 * conducted by DefineRelation() and friends.
@@ -776,7 +772,7 @@ DefineDomain(CreateDomainStmt *stmt)
 				   receiveProcedure,	/* receive procedure */
 				   sendProcedure,		/* send procedure */
 				   analyzeProcedure,	/* analyze procedure */
-				   basetypelem, /* element type ID */
+				   typelem,		/* element type ID */
 				   basetypeoid, /* base type ID */
 				   defaultValue,	/* default type value (text) */
 				   defaultValueBin,		/* default type value (binary) */

src/backend/optimizer/prep/preptlist.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.80 2006/03/05 15:58:31 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.81 2006/04/05 22:11:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -249,7 +249,7 @@ expand_targetlist(List *tlist, int command_type,
 													  true,		/* isnull */
 													  att_tup->attbyval);
 						new_expr = coerce_to_domain(new_expr,
-													InvalidOid,
+													InvalidOid, -1,
 													atttype,
 													COERCE_IMPLICIT_CAST,
 													false,