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Implement SQL-compliant treatment of row comparisons for < <= > >= cases

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(previously we only did = and <> correctly).  Also, allow row comparisons
with any operators that are in btree opclasses, not only those with these
specific names.  This gets rid of a whole lot of indefensible assumptions
about the behavior of particular operators based on their names ... though
it's still true that IN and NOT IN expand to "= ANY".  The patch adds a
RowCompareExpr expression node type, and makes some changes in the
representation of ANY/ALL/ROWCOMPARE SubLinks so that they can share code
with RowCompareExpr.

I have not yet done anything about making RowCompareExpr an indexable
operator, but will look at that soon.

initdb forced due to changes in stored rules.
This commit is contained in:
Tom Lane
2005-12-28 01:30:02 +00:00
parent a37422e042
commit 6e07709760
26 changed files with 1452 additions and 659 deletions
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160
src/backend/utils/adt/ruleutils.c
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@@ -3,7 +3,7 @@
* back to source text
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.210 2005/12/10 19:21:03 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.211 2005/12/28 01:30:00 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@@ -215,7 +215,6 @@ static void printSubscripts(ArrayRef *aref, deparse_context *context);
static char *generate_relation_name(Oid relid);
static char *generate_function_name(Oid funcid, int nargs, Oid *argtypes);
static char *generate_operator_name(Oid operid, Oid arg1, Oid arg2);
static void print_operator_name(StringInfo buf, List *opname);
static text *string_to_text(char *str);
#define only_marker(rte) ((rte)->inh ? "" : "ONLY ")
@@ -3106,6 +3105,7 @@ get_rule_expr(Node *node, deparse_context *context,
break;
case PARAM_NUM:
case PARAM_EXEC:
case PARAM_SUBLINK:
appendStringInfo(buf, "$%d", param->paramid);
break;
default:
@@ -3514,6 +3514,50 @@ get_rule_expr(Node *node, deparse_context *context,
}
break;
case T_RowCompareExpr:
{
RowCompareExpr *rcexpr = (RowCompareExpr *) node;
ListCell *arg;
char *sep;
/*
* SQL99 allows "ROW" to be omitted when there is more than
* one column, but for simplicity we always print it.
*/
appendStringInfo(buf, "(ROW(");
sep = "";
foreach(arg, rcexpr->largs)
{
Node *e = (Node *) lfirst(arg);
appendStringInfoString(buf, sep);
get_rule_expr(e, context, true);
sep = ", ";
}
/*
* We assume that the name of the first-column operator
* will do for all the rest too. This is definitely
* open to failure, eg if some but not all operators
* were renamed since the construct was parsed, but there
* seems no way to be perfect.
*/
appendStringInfo(buf, ") %s ROW(",
generate_operator_name(linitial_oid(rcexpr->opnos),
exprType(linitial(rcexpr->largs)),
exprType(linitial(rcexpr->rargs))));
sep = "";
foreach(arg, rcexpr->rargs)
{
Node *e = (Node *) lfirst(arg);
appendStringInfoString(buf, sep);
get_rule_expr(e, context, true);
sep = ", ";
}
appendStringInfo(buf, "))");
}
break;
case T_CoalesceExpr:
{
CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
@@ -3967,6 +4011,7 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
{
StringInfo buf = context->buf;
Query *query = (Query *) (sublink->subselect);
char *opname = NULL;
bool need_paren;
if (sublink->subLinkType == ARRAY_SUBLINK)
@@ -3974,25 +4019,67 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
else
appendStringInfoChar(buf, '(');
if (sublink->lefthand != NIL)
/*
* Note that we print the name of only the first operator, when there
* are multiple combining operators. This is an approximation that
* could go wrong in various scenarios (operators in different schemas,
* renamed operators, etc) but there is not a whole lot we can do about
* it, since the syntax allows only one operator to be shown.
*/
if (sublink->testexpr)
{
need_paren = (list_length(sublink->lefthand) > 1);
if (need_paren)
if (IsA(sublink->testexpr, OpExpr))
{
/* single combining operator */
OpExpr *opexpr = (OpExpr *) sublink->testexpr;
get_rule_expr(linitial(opexpr->args), context, true);
opname = generate_operator_name(opexpr->opno,
exprType(linitial(opexpr->args)),
exprType(lsecond(opexpr->args)));
}
else if (IsA(sublink->testexpr, BoolExpr))
{
/* multiple combining operators, = or <> cases */
char *sep;
ListCell *l;
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) sublink->lefthand, context, true);
if (need_paren)
sep = "";
foreach(l, ((BoolExpr *) sublink->testexpr)->args)
{
OpExpr *opexpr = (OpExpr *) lfirst(l);
Assert(IsA(opexpr, OpExpr));
appendStringInfoString(buf, sep);
get_rule_expr(linitial(opexpr->args), context, true);
if (!opname)
opname = generate_operator_name(opexpr->opno,
exprType(linitial(opexpr->args)),
exprType(lsecond(opexpr->args)));
sep = ", ";
}
appendStringInfoChar(buf, ')');
appendStringInfoChar(buf, ' ');
}
else if (IsA(sublink->testexpr, RowCompareExpr))
{
/* multiple combining operators, < <= > >= cases */
RowCompareExpr *rcexpr = (RowCompareExpr *) sublink->testexpr;
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) rcexpr->largs, context, true);
opname = generate_operator_name(linitial_oid(rcexpr->opnos),
exprType(linitial(rcexpr->largs)),
exprType(linitial(rcexpr->rargs)));
appendStringInfoChar(buf, ')');
}
else
elog(ERROR, "unrecognized testexpr type: %d",
(int) nodeTag(sublink->testexpr));
}
need_paren = true;
/*
* XXX we regurgitate the originally given operator name, with or without
* schema qualification. This is not necessarily 100% right but it's the
* best we can do, since the operators actually used might not all be in
* the same schema.
*/
switch (sublink->subLinkType)
{
case EXISTS_SUBLINK:
@@ -4000,27 +4087,18 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
break;
case ANY_SUBLINK:
if (list_length(sublink->operName) == 1 &&
strcmp(strVal(linitial(sublink->operName)), "=") == 0)
{
/* Represent = ANY as IN */
appendStringInfo(buf, "IN ");
}
if (strcmp(opname, "=") == 0) /* Represent = ANY as IN */
appendStringInfo(buf, " IN ");
else
{
print_operator_name(buf, sublink->operName);
appendStringInfo(buf, " ANY ");
}
appendStringInfo(buf, " %s ANY ", opname);
break;
case ALL_SUBLINK:
print_operator_name(buf, sublink->operName);
appendStringInfo(buf, " ALL ");
appendStringInfo(buf, " %s ALL ", opname);
break;
case MULTIEXPR_SUBLINK:
print_operator_name(buf, sublink->operName);
appendStringInfoChar(buf, ' ');
case ROWCOMPARE_SUBLINK:
appendStringInfo(buf, " %s ", opname);
break;
case EXPR_SUBLINK:
@@ -4812,30 +4890,6 @@ generate_operator_name(Oid operid, Oid arg1, Oid arg2)
return buf.data;
}
/*
* Print out a possibly-qualified operator name
*/
static void
print_operator_name(StringInfo buf, List *opname)
{
ListCell *op = list_head(opname);
int nnames = list_length(opname);
if (nnames == 1)
appendStringInfoString(buf, strVal(lfirst(op)));
else
{
appendStringInfo(buf, "OPERATOR(");
while (nnames-- > 1)
{
appendStringInfo(buf, "%s.",
quote_identifier(strVal(lfirst(op))));
op = lnext(op);
}
appendStringInfo(buf, "%s)", strVal(lfirst(op)));
}
}
/*
* Given a C string, produce a TEXT datum.
*