tests to return the correct results per SQL9x when given NULL inputs.
Reimplement these tests as well as IS [NOT] NULL to have their own
expression node types, instead of depending on special functions.
From Joe Conway, with a little help from Tom Lane.
/*
* parse function
* This code is confusing because the database can accept
* relation.column, column.function, or relation.column.function.
* In these cases, funcname is the last parameter, and fargs are
* the rest.
*
* It can also be called as func(col) or func(col,col).
* In this case, Funcname is the part before parens, and fargs
* are the part in parens.
*
*/
Node *
ParseFuncOrColumn(ParseState *pstate, char *funcname, List *fargs,
bool agg_star, bool agg_distinct,
int precedence)
1. If there is exactly one pg_operator entry of the right name and oprkind,
oper() and related routines would return that entry whether its input type
had anything to do with the request or not. This is just premature
optimization: we shouldn't return the single candidate until after we verify
that it really is a valid candidate, ie, is at least coercion-compatible
with the given types.
2. oper() and related routines only promise a coercion-compatible result.
Unfortunately, there were quite a few callers that assumed the returned
operator is binary-compatible with the given datatype; they would proceed
to call it without making any datatype coercions. These callers include
sorting, grouping, aggregation, and VACUUM ANALYZE. In general I think
it is appropriate for these callers to require an exact or binary-compatible
match, so I've added a new routine compatible_oper() that only succeeds if
it can find an operator that doesn't require any run-time conversions.
Callers now call oper() or compatible_oper() depending on whether they are
prepared to deal with type conversion or not.
The upshot of these bugs is revealed by the following silliness in PL/Tcl's
selftest: it creates an operator @< on int4, and then tries to use it to
sort a char(N) column. The system would let it do that :-( (and evidently
has done so since 6.3 :-( :-(). The result in this case was just a silly
sort order, but the reverse combination would've provoked coredump from
trying to dereference integers. With this fix you get more reasonable
behavior:
pltcl_test=# select * from T_pkey1 order by key1, key2 using @<;
ERROR: Unable to identify an operator '@<' for types 'bpchar' and 'bpchar'
You will have to retype this query using an explicit cast
clause with an alias is a <subquery> and therefore hides table references
appearing within it, according to the spec. This is the same as the
preliminary patch I posted to pgsql-patches yesterday, plus some really
grotty code in ruleutils.c to reverse-list a query tree with the correct
alias name depending on context. I'd rather not have done that, but unless
we want to force another initdb for 7.1, there's no other way for now.
maintained for each cache entry. A cache entry will not be freed until
the matching ReleaseSysCache call has been executed. This eliminates
worries about cache entries getting dropped while still in use. See
my posting to pg-hackers of even date for more info.
took some rejiggering of typename and ACL parsing, as well as moving
parse_analyze call out of parser(). Restructure postgres.c processing
so that parse analysis and rewrite are skipped when in abort-transaction
state. Only COMMIT and ABORT statements will be processed beyond the raw
parser() phase. This addresses problem of parser failing with database access
errors while in aborted state (see pghackers discussions around 7/28/00).
Also fix some bugs with COMMIT/ABORT statements appearing in the middle of
a single query input string.
Function, operator, and aggregate arguments/results can now use full
TypeName production, in particular foo[] for array types.
DROP OPERATOR and COMMENT ON OPERATOR were broken for unary operators.
Allow CREATE AGGREGATE to accept unquoted numeric constants for initcond.
SQL92 semantics, including support for ALL option. All three can be used
in subqueries and views. DISTINCT and ORDER BY work now in views, too.
This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
where the SELECT yields different datatypes than the INSERT needs. I did
that by making UNION subqueries and SELECT in INSERT be treated like
subselects-in-FROM, thereby allowing an extra level of targetlist where the
datatype conversions can be inserted safely.
INITDB NEEDED!
(Don't forget that an alias is required.) Views reimplemented as expanding
to subselect-in-FROM. Grouping, aggregates, DISTINCT in views actually
work now (he says optimistically). No UNION support in subselects/views
yet, but I have some ideas about that. Rule-related permissions checking
moved out of rewriter and into executor.
INITDB REQUIRED!
from Param nodes, per discussion a few days ago on pghackers. Add new
expression node type FieldSelect that implements the functionality where
it's actually needed. Clean up some other unused fields in Func nodes
as well.
NOTE: initdb forced due to change in stored expression trees for rules.
inputs have been converted to newstyle. This should go a long way towards
fixing our portability problems with platforms where char and short
parameters are passed differently from int-width parameters. Still
more to do for the Alpha port however.
the oper field should be a valid Node structure so it can be dumped by
outfuncs.c without risk of coredump. (We had been using a raw pointer
to character string, which surely is NOT a valid Node.) This doesn't
cause any backwards compatibility problems for stored rules, since
raw unanalyzed parsetrees are never stored.
had already been transformed. This led to failure in examples like
UPDATE table SET fld = (SELECT ...). Repair this, and revise the
comments to explain that transformExpr has to be robust against this
condition. Someday we might want to fix the callers so that
transformExpr is never invoked on its own output, but that someday
is not today.
Implement TIME WITH TIME ZONE type (timetz internal type).
Remap length() for character strings to CHAR_LENGTH() for SQL92
and to remove the ambiguity with geometric length() functions.
Keep length() for character strings for backward compatibility.
Shrink stored views by removing internal column name list from visible rte.
Implement min(), max() for time and timetz data types.
Implement conversion of TIME to INTERVAL.
Implement abs(), mod(), fac() for the int8 data type.
Rename some math functions to generic names:
round(), sqrt(), cbrt(), pow(), etc.
Rename NUMERIC power() function to pow().
Fix int2 factorial to calculate result in int4.
Enhance the Oracle compatibility function translate() to work with string
arguments (from Edwin Ramirez).
Modify pg_proc system table to remove OID holes.
such as bpchar(char_expression, N), and pull out the attrtypmod that
the function is coercing to. This allows correct deduction of the
column type in examples such as
CREATE VIEW v AS SELECT f1::char(8) FROM tbl;
Formerly we labeled v's column as char-of-unknown-length not char(8).
Also, this change causes the parser not to insert a redundant length
coercion function if the user has explicitly casted an INSERT or UPDATE
expression to the right length.
integers) to be strings instead of 'double'. We convert from string form
to internal representation only after type resolution has determined the
correct type for the constant. This eliminates loss-of-precision worries
and gets rid of the change in behavior seen at 17 digits with the
previous kluge.
represent the result of a binary-compatible type coercion. At runtime
it just evaluates its argument --- but during type resolution, exprType
will pick up the output type of the RelabelType node instead of the type
of the argument. This solves some longstanding problems with dropped
type coercions, an example being 'select now()::abstime::int4' which
used to produce date-formatted output, not an integer, because the
coercion to int4 was dropped on the floor.
SELECT a FROM t1 tx (a);
Allow join syntax, including queries like
SELECT * FROM t1 NATURAL JOIN t2;
Update RTE structure to hold column aliases in an Attr structure.
SQL cast constructs can be performed during expression transformation
instead of during parsing. This allows constructs like x::numeric(9,2)
and x::int2::float8 to behave as one would expect.
SELECT null::text;
SELECT int4fac(null);
work as expected now. In some cases a NULL must be surrounded by
parentheses:
SELECT 2 + null; fails
SELECT 2 + (null); OK
This is a grammatical ambiguity that seems difficult to avoid. Other
than that, NULLs seem to behave about like you'd expect. The internal
implementation is that NULL constants are typed as UNKNOWN (like
untyped string constants) until the parser can deduce the right type.
>go about this. That will risk breaking existing applications that use
>those names as column names.
>
>It should actually almost work to write sq.nextval as things stand,
>because Postgres has for a long time considered table.function and
>function(table) to be interchangeable notations for certain kinds of
>functions. nextval doesn't seem to be one of that kind of function,
>at the moment. I'd suggest leaving the grammar as it was, and taking a
>look at ParseFuncOrColumn in parse_func.c to see if you can't persuade
>it to accept the sequence functions in that style.
OK, good point. I tried to implement it somewhere else and ended up
extending transformAttr. Attached you'll find the patch.
Jeroen van Vianen
yet, but at least we can give a better error message:
regression=> select count(distinct f1) from int4_tbl;
ERROR: aggregate(DISTINCT ...) is not implemented yet
instead of 'parser: parse error at or near distinct'.
subselects can only appear on the righthand side of a binary operator.
That's still true for quantified predicates like x = ANY (SELECT ...),
but a subselect that delivers a single result can now appear anywhere
in an expression. This is implemented by changing EXPR_SUBLINK sublinks
to represent just the (SELECT ...) expression, without any 'left hand
side' or combining operator --- so they're now more like EXISTS_SUBLINK.
To handle the case of '(x, y, z) = (SELECT ...)', I added a new sublink
type MULTIEXPR_SUBLINK, which acts just like EXPR_SUBLINK used to.
But the grammar will only generate one for a multiple-left-hand-side
row expression.
Almost worked before, but forgot one place to check.
Reported by Tatsuo Ishii.
Still does not do the right thing if inserting into a non-string target
column. Should look for a type coersion later, but doesn't.
documented intepretation of the lefthand and oper fields. Fix a number of
obscure problems while at it --- for example, the old code failed if the parser
decided to insert a type-coercion function just below the operator of a
SubLink.
CAUTION: this will break stored rules that contain subplans. You may
need to initdb.
of the SELECT part of the statement is just like a plain SELECT. All
INSERT-specific processing happens after the SELECT parsing is done.
This eliminates many problems, e.g. INSERT ... SELECT ... GROUP BY using
the wrong column labels. Ensure that DEFAULT clauses are coerced to
the target column type, whether or not stored clause produces the right
type. Substantial cleanup of parser's array support.
Peter Eisentraut
Tom Lane
Bruce Momjian
Thomas G. Lockhart