transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
{
	bool		is_serial;
	bool		saw_nullable;
	bool		saw_default;
	bool		saw_identity;
	bool		saw_generated;
	ListCell   *clist;

	cxt->columns = lappend(cxt->columns, column);

	/* Check for SERIAL pseudo-types */
	is_serial = false;
	if (column->typeName
		&& list_length(column->typeName->names) == 1
		&& !column->typeName->pct_type)
	{
		char	   *typname = strVal(linitial(column->typeName->names));

		if (strcmp(typname, "smallserial") == 0 ||
			strcmp(typname, "serial2") == 0)
		{
			is_serial = true;
			column->typeName->names = NIL;
			column->typeName->typeOid = INT2OID;
		}
		else if (strcmp(typname, "serial") == 0 ||
				 strcmp(typname, "serial4") == 0)
		{
			is_serial = true;
			column->typeName->names = NIL;
			column->typeName->typeOid = INT4OID;
		}
		else if (strcmp(typname, "bigserial") == 0 ||
				 strcmp(typname, "serial8") == 0)
		{
			is_serial = true;
			column->typeName->names = NIL;
			column->typeName->typeOid = INT8OID;
		}

		/*
		 * We have to reject "serial[]" explicitly, because once we've set
		 * typeid, LookupTypeName won't notice arrayBounds.  We don't need any
		 * special coding for serial(typmod) though.
		 */
		if (is_serial && column->typeName->arrayBounds != NIL)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("array of serial is not implemented"),
					 parser_errposition(cxt->pstate,
										column->typeName->location)));
	}

	/* Do necessary work on the column type declaration */
	if (column->typeName)
		transformColumnType(cxt, column);

	/* Special actions for SERIAL pseudo-types */
	if (is_serial)
	{
		char	   *snamespace;
		char	   *sname;
		char	   *qstring;
		A_Const    *snamenode;
		TypeCast   *castnode;
		FuncCall   *funccallnode;
		Constraint *constraint;

		generateSerialExtraStmts(cxt, column,
								 column->typeName->typeOid, NIL,
								 false, false,
								 &snamespace, &sname);

		/*
		 * Create appropriate constraints for SERIAL.  We do this in full,
		 * rather than shortcutting, so that we will detect any conflicting
		 * constraints the user wrote (like a different DEFAULT).
		 *
		 * Create an expression tree representing the function call
		 * nextval('sequencename').  We cannot reduce the raw tree to cooked
		 * form until after the sequence is created, but there's no need to do
		 * so.
		 */
		qstring = quote_qualified_identifier(snamespace, sname);
		snamenode = makeNode(A_Const);
		snamenode->val.type = T_String;
		snamenode->val.val.str = qstring;
		snamenode->location = -1;
		castnode = makeNode(TypeCast);
		castnode->typeName = SystemTypeName("regclass");
		castnode->arg = (Node *) snamenode;
		castnode->location = -1;
		funccallnode = makeFuncCall(SystemFuncName("nextval"),
									list_make1(castnode),
									COERCE_EXPLICIT_CALL,
									-1);
		constraint = makeNode(Constraint);
		constraint->contype = CONSTR_DEFAULT;
		constraint->location = -1;
		constraint->raw_expr = (Node *) funccallnode;
		constraint->cooked_expr = NULL;
		column->constraints = lappend(column->constraints, constraint);

		constraint = makeNode(Constraint);
		constraint->contype = CONSTR_NOTNULL;
		constraint->location = -1;
		column->constraints = lappend(column->constraints, constraint);
	}

	/* Process column constraints, if any... */
	transformConstraintAttrs(cxt, column->constraints);

	saw_nullable = false;
	saw_default = false;
	saw_identity = false;
	saw_generated = false;

	foreach(clist, column->constraints)
	{
		Constraint *constraint = lfirst_node(Constraint, clist);

		switch (constraint->contype)
		{
			case CONSTR_NULL:
				if (saw_nullable && column->is_not_null)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->is_not_null = false;
				saw_nullable = true;
				break;

			case CONSTR_NOTNULL:
				if (saw_nullable && !column->is_not_null)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->is_not_null = true;
				saw_nullable = true;
				break;

			case CONSTR_DEFAULT:
				if (saw_default)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("multiple default values specified for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->raw_default = constraint->raw_expr;
				Assert(constraint->cooked_expr == NULL);
				saw_default = true;
				break;

			case CONSTR_IDENTITY:
				{
					Type		ctype;
					Oid			typeOid;

					if (cxt->ofType)
						ereport(ERROR,
								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
								 errmsg("identity columns are not supported on typed tables")));
					if (cxt->partbound)
						ereport(ERROR,
								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
								 errmsg("identity columns are not supported on partitions")));

					ctype = typenameType(cxt->pstate, column->typeName, NULL);
					typeOid = ((Form_pg_type) GETSTRUCT(ctype))->oid;
					ReleaseSysCache(ctype);

					if (saw_identity)
						ereport(ERROR,
								(errcode(ERRCODE_SYNTAX_ERROR),
								 errmsg("multiple identity specifications for column \"%s\" of table \"%s\"",
										column->colname, cxt->relation->relname),
								 parser_errposition(cxt->pstate,
													constraint->location)));

					generateSerialExtraStmts(cxt, column,
											 typeOid, constraint->options,
											 true, false,
											 NULL, NULL);

					column->identity = constraint->generated_when;
					saw_identity = true;

					/* An identity column is implicitly NOT NULL */
					if (saw_nullable && !column->is_not_null)
						ereport(ERROR,
								(errcode(ERRCODE_SYNTAX_ERROR),
								 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
										column->colname, cxt->relation->relname),
								 parser_errposition(cxt->pstate,
													constraint->location)));
					column->is_not_null = true;
					saw_nullable = true;
					break;
				}

			case CONSTR_GENERATED:
				if (cxt->ofType)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("generated columns are not supported on typed tables")));
				if (cxt->partbound)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("generated columns are not supported on partitions")));

				if (saw_generated)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("multiple generation clauses specified for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->generated = ATTRIBUTE_GENERATED_STORED;
				column->raw_default = constraint->raw_expr;
				Assert(constraint->cooked_expr == NULL);
				saw_generated = true;
				break;

			case CONSTR_CHECK:
				cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
				break;

			case CONSTR_PRIMARY:
				if (cxt->isforeign)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("primary key constraints are not supported on foreign tables"),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				/* FALL THRU */

			case CONSTR_UNIQUE:
				if (cxt->isforeign)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("unique constraints are not supported on foreign tables"),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				if (constraint->keys == NIL)
					constraint->keys = list_make1(makeString(column->colname));
				cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
				break;

			case CONSTR_EXCLUSION:
				/* grammar does not allow EXCLUDE as a column constraint */
				elog(ERROR, "column exclusion constraints are not supported");
				break;

			case CONSTR_FOREIGN:
				if (cxt->isforeign)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("foreign key constraints are not supported on foreign tables"),
							 parser_errposition(cxt->pstate,
												constraint->location)));

				/*
				 * Fill in the current attribute's name and throw it into the
				 * list of FK constraints to be processed later.
				 */
				constraint->fk_attrs = list_make1(makeString(column->colname));
				cxt->fkconstraints = lappend(cxt->fkconstraints, constraint);
				break;

			case CONSTR_ATTR_DEFERRABLE:
			case CONSTR_ATTR_NOT_DEFERRABLE:
			case CONSTR_ATTR_DEFERRED:
			case CONSTR_ATTR_IMMEDIATE:
				/* transformConstraintAttrs took care of these */
				break;

			default:
				elog(ERROR, "unrecognized constraint type: %d",
					 constraint->contype);
				break;
		}

		if (saw_default && saw_identity)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("both default and identity specified for column \"%s\" of table \"%s\"",
							column->colname, cxt->relation->relname),
					 parser_errposition(cxt->pstate,
										constraint->location)));

		if (saw_default && saw_generated)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("both default and generation expression specified for column \"%s\" of table \"%s\"",
							column->colname, cxt->relation->relname),
					 parser_errposition(cxt->pstate,
										constraint->location)));

		if (saw_identity && saw_generated)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("both identity and generation expression specified for column \"%s\" of table \"%s\"",
							column->colname, cxt->relation->relname),
					 parser_errposition(cxt->pstate,
										constraint->location)));
	}

	/*
	 * If needed, generate ALTER FOREIGN TABLE ALTER COLUMN statement to add
	 * per-column foreign data wrapper options to this column after creation.
	 */
	if (column->fdwoptions != NIL)
	{
		AlterTableStmt *stmt;
		AlterTableCmd *cmd;

		cmd = makeNode(AlterTableCmd);
		cmd->subtype = AT_AlterColumnGenericOptions;
		cmd->name = column->colname;
		cmd->def = (Node *) column->fdwoptions;
		cmd->behavior = DROP_RESTRICT;
		cmd->missing_ok = false;

		stmt = makeNode(AlterTableStmt);
		stmt->relation = cxt->relation;
		stmt->cmds = NIL;
		stmt->objtype = OBJECT_FOREIGN_TABLE;
		stmt->cmds = lappend(stmt->cmds, cmd);

		cxt->alist = lappend(cxt->alist, stmt);
	}
}
transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
{
	bool		is_serial;
	bool		saw_nullable;
	bool		saw_default;
	bool		saw_identity;
	bool		saw_generated;
	ListCell   *clist;

	cxt->columns = lappend(cxt->columns, column);

	 
	is_serial = false;
	if (column->typeName
		&& list_length(column->typeName->names) == 1
		&& !column->typeName->pct_type)
	{
		char	   *typname = strVal(linitial(column->typeName->names));

		if (strcmp(typname, "smallserial") == 0 ||
			strcmp(typname, "serial2") == 0)
		{
			is_serial = true;
			column->typeName->names = NIL;
			column->typeName->typeOid = INT2OID;
		}
		else if (strcmp(typname, "serial") == 0 ||
				 strcmp(typname, "serial4") == 0)
		{
			is_serial = true;
			column->typeName->names = NIL;
			column->typeName->typeOid = INT4OID;
		}
		else if (strcmp(typname, "bigserial") == 0 ||
				 strcmp(typname, "serial8") == 0)
		{
			is_serial = true;
			column->typeName->names = NIL;
			column->typeName->typeOid = INT8OID;
		}

		 
		if (is_serial && column->typeName->arrayBounds != NIL)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("array of serial is not implemented"),
					 parser_errposition(cxt->pstate,
										column->typeName->location)));
	}

	 
	if (column->typeName)
		transformColumnType(cxt, column);

	 
	if (is_serial)
	{
		char	   *snamespace;
		char	   *sname;
		char	   *qstring;
		A_Const    *snamenode;
		TypeCast   *castnode;
		FuncCall   *funccallnode;
		Constraint *constraint;

		generateSerialExtraStmts(cxt, column,
								 column->typeName->typeOid, NIL,
								 false, false,
								 &snamespace, &sname);

		 
		qstring = quote_qualified_identifier(snamespace, sname);
		snamenode = makeNode(A_Const);
		snamenode->val.type = T_String;
		snamenode->val.val.str = qstring;
		snamenode->location = -1;
		castnode = makeNode(TypeCast);
		castnode->typeName = SystemTypeName("regclass");
		castnode->arg = (Node *) snamenode;
		castnode->location = -1;
		funccallnode = makeFuncCall(SystemFuncName("nextval"),
									list_make1(castnode),
									COERCE_EXPLICIT_CALL,
									-1);
		constraint = makeNode(Constraint);
		constraint->contype = CONSTR_DEFAULT;
		constraint->location = -1;
		constraint->raw_expr = (Node *) funccallnode;
		constraint->cooked_expr = NULL;
		column->constraints = lappend(column->constraints, constraint);

		constraint = makeNode(Constraint);
		constraint->contype = CONSTR_NOTNULL;
		constraint->location = -1;
		column->constraints = lappend(column->constraints, constraint);
	}

	 
	transformConstraintAttrs(cxt, column->constraints);

	saw_nullable = false;
	saw_default = false;
	saw_identity = false;
	saw_generated = false;

	foreach(clist, column->constraints)
	{
		Constraint *constraint = lfirst_node(Constraint, clist);

		switch (constraint->contype)
		{
			case CONSTR_NULL:
				if (saw_nullable && column->is_not_null)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->is_not_null = false;
				saw_nullable = true;
				break;

			case CONSTR_NOTNULL:
				if (saw_nullable && !column->is_not_null)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->is_not_null = true;
				saw_nullable = true;
				break;

			case CONSTR_DEFAULT:
				if (saw_default)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("multiple default values specified for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->raw_default = constraint->raw_expr;
				Assert(constraint->cooked_expr == NULL);
				saw_default = true;
				break;

			case CONSTR_IDENTITY:
				{
					Type		ctype;
					Oid			typeOid;

					if (cxt->ofType)
						ereport(ERROR,
								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
								 errmsg("identity columns are not supported on typed tables")));
					if (cxt->partbound)
						ereport(ERROR,
								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
								 errmsg("identity columns are not supported on partitions")));

					ctype = typenameType(cxt->pstate, column->typeName, NULL);
					typeOid = ((Form_pg_type) GETSTRUCT(ctype))->oid;
					ReleaseSysCache(ctype);

					if (saw_identity)
						ereport(ERROR,
								(errcode(ERRCODE_SYNTAX_ERROR),
								 errmsg("multiple identity specifications for column \"%s\" of table \"%s\"",
										column->colname, cxt->relation->relname),
								 parser_errposition(cxt->pstate,
													constraint->location)));

					generateSerialExtraStmts(cxt, column,
											 typeOid, constraint->options,
											 true, false,
											 NULL, NULL);

					column->identity = constraint->generated_when;
					saw_identity = true;

					 
					if (saw_nullable && !column->is_not_null)
						ereport(ERROR,
								(errcode(ERRCODE_SYNTAX_ERROR),
								 errmsg("conflicting NULL/NOT NULL declarations for column \"%s\" of table \"%s\"",
										column->colname, cxt->relation->relname),
								 parser_errposition(cxt->pstate,
													constraint->location)));
					column->is_not_null = true;
					saw_nullable = true;
					break;
				}

			case CONSTR_GENERATED:
				if (cxt->ofType)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("generated columns are not supported on typed tables")));
				if (cxt->partbound)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("generated columns are not supported on partitions")));

				if (saw_generated)
					ereport(ERROR,
							(errcode(ERRCODE_SYNTAX_ERROR),
							 errmsg("multiple generation clauses specified for column \"%s\" of table \"%s\"",
									column->colname, cxt->relation->relname),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				column->generated = ATTRIBUTE_GENERATED_STORED;
				column->raw_default = constraint->raw_expr;
				Assert(constraint->cooked_expr == NULL);
				saw_generated = true;
				break;

			case CONSTR_CHECK:
				cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
				break;

			case CONSTR_PRIMARY:
				if (cxt->isforeign)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("primary key constraints are not supported on foreign tables"),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				 

			case CONSTR_UNIQUE:
				if (cxt->isforeign)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("unique constraints are not supported on foreign tables"),
							 parser_errposition(cxt->pstate,
												constraint->location)));
				if (constraint->keys == NIL)
					constraint->keys = list_make1(makeString(column->colname));
				cxt->ixconstraints = lappend(cxt->ixconstraints, constraint);
				break;

			case CONSTR_EXCLUSION:
				 
				elog(ERROR, "column exclusion constraints are not supported");
				break;

			case CONSTR_FOREIGN:
				if (cxt->isforeign)
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("foreign key constraints are not supported on foreign tables"),
							 parser_errposition(cxt->pstate,
												constraint->location)));

				 
				constraint->fk_attrs = list_make1(makeString(column->colname));
				cxt->fkconstraints = lappend(cxt->fkconstraints, constraint);
				break;

			case CONSTR_ATTR_DEFERRABLE:
			case CONSTR_ATTR_NOT_DEFERRABLE:
			case CONSTR_ATTR_DEFERRED:
			case CONSTR_ATTR_IMMEDIATE:
				 
				break;

			default:
				elog(ERROR, "unrecognized constraint type: %d",
					 constraint->contype);
				break;
		}

		if (saw_default && saw_identity)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("both default and identity specified for column \"%s\" of table \"%s\"",
							column->colname, cxt->relation->relname),
					 parser_errposition(cxt->pstate,
										constraint->location)));

		if (saw_default && saw_generated)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("both default and generation expression specified for column \"%s\" of table \"%s\"",
							column->colname, cxt->relation->relname),
					 parser_errposition(cxt->pstate,
										constraint->location)));

		if (saw_identity && saw_generated)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("both identity and generation expression specified for column \"%s\" of table \"%s\"",
							column->colname, cxt->relation->relname),
					 parser_errposition(cxt->pstate,
										constraint->location)));
	}

	 
	if (column->fdwoptions != NIL)
	{
		AlterTableStmt *stmt;
		AlterTableCmd *cmd;

		cmd = makeNode(AlterTableCmd);
		cmd->subtype = AT_AlterColumnGenericOptions;
		cmd->name = column->colname;
		cmd->def = (Node *) column->fdwoptions;
		cmd->behavior = DROP_RESTRICT;
		cmd->missing_ok = false;

		stmt = makeNode(AlterTableStmt);
		stmt->relation = cxt->relation;
		stmt->cmds = NIL;
		stmt->objtype = OBJECT_FOREIGN_TABLE;
		stmt->cmds = lappend(stmt->cmds, cmd);

		cxt->alist = lappend(cxt->alist, stmt);
	}
}