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Attached are two patches to implement and document anonymous composite

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types for Table Functions, as previously proposed on HACKERS. Here is a
brief explanation:

1. Creates a new pg_type typtype: 'p' for pseudo type (currently either
     'b' for base or 'c' for catalog, i.e. a class).

2. Creates new builtin type of typtype='p' named RECORD. This is the
     first of potentially several pseudo types.

3. Modify FROM clause grammer to accept:
     SELECT * FROM my_func() AS m(colname1 type1, colname2 type1, ...)
     where m is the table alias, colname1, etc are the column names, and
     type1, etc are the column types.

4. When typtype == 'p' and the function return type is RECORD, a list
     of column defs is required, and when typtype != 'p', it is
disallowed.

5. A check was added to ensure that the tupdesc provide via the parser
     and the actual return tupdesc match in number and type of
attributes.

When creating a function you can do:
     CREATE FUNCTION foo(text) RETURNS setof RECORD ...

When using it you can do:
     SELECT * from foo(sqlstmt) AS (f1 int, f2 text, f3 timestamp)
       or
     SELECT * from foo(sqlstmt) AS f(f1 int, f2 text, f3 timestamp)
       or
     SELECT * from foo(sqlstmt) f(f1 int, f2 text, f3 timestamp)

Included in the patches are adjustments to the regression test sql and
expected files, and documentation.

p.s.
     This potentially solves (or at least improves) the issue of builtin
     Table Functions. They can be bootstrapped as returning RECORD, and
     we can wrap system views around them with properly specified column
     defs. For example:

     CREATE VIEW pg_settings AS
       SELECT s.name, s.setting
       FROM show_all_settings()AS s(name text, setting text);

     Then we can also add the UPDATE RULE that I previously posted to
     pg_settings, and have pg_settings act like a virtual table, allowing
     settings to be queried and set.


Joe Conway
This commit is contained in:
Bruce Momjian
2002-08-04 19:48:11 +00:00
parent 35d39ba081
commit 9218689b69
19 changed files with 677 additions and 280 deletions
Download Patch File Download Diff File Expand all files Collapse all files

336
src/backend/parser/parse_relation.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.71 2002/08/02 18:15:07 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.72 2002/08/04 19:48:10 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -699,12 +699,14 @@ RangeTblEntry *
addRangeTableEntryForFunction(ParseState *pstate,
char *funcname,
Node *funcexpr,
Alias *alias,
RangeFunction *rangefunc,
bool inFromCl)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
Oid funcrettype = exprType(funcexpr);
Oid funcrelid;
char functyptype;
Alias *alias = rangefunc->alias;
List *coldeflist = rangefunc->coldeflist;
Alias *eref;
int numaliases;
int varattno;
@ -713,6 +715,7 @@ addRangeTableEntryForFunction(ParseState *pstate,
rte->relid = InvalidOid;
rte->subquery = NULL;
rte->funcexpr = funcexpr;
rte->coldeflist = coldeflist;
rte->alias = alias;
eref = alias ? (Alias *) copyObject(alias) : makeAlias(funcname, NIL);
@ -724,47 +727,56 @@ addRangeTableEntryForFunction(ParseState *pstate,
* Now determine if the function returns a simple or composite type,
* and check/add column aliases.
*/
funcrelid = typeidTypeRelid(funcrettype);
functyptype = typeid_get_typtype(funcrettype);
if (OidIsValid(funcrelid))
if (functyptype == 'c')
{
/*
* Composite data type, i.e. a table's row type
*
* Get the rel's relcache entry. This access ensures that we have an
* up-to-date relcache entry for the rel.
* Named composite data type, i.e. a table's row type
*/
Relation rel;
int maxattrs;
Oid funcrelid = typeidTypeRelid(funcrettype);
rel = heap_open(funcrelid, AccessShareLock);
/*
* Since the rel is open anyway, let's check that the number of column
* aliases is reasonable.
*/
maxattrs = RelationGetNumberOfAttributes(rel);
if (maxattrs < numaliases)
elog(ERROR, "Table \"%s\" has %d columns available but %d columns specified",
RelationGetRelationName(rel), maxattrs, numaliases);
/* fill in alias columns using actual column names */
for (varattno = numaliases; varattno < maxattrs; varattno++)
if (OidIsValid(funcrelid))
{
char *attrname;
/*
* Get the rel's relcache entry. This access ensures that we have an
* up-to-date relcache entry for the rel.
*/
Relation rel;
int maxattrs;
attrname = pstrdup(NameStr(rel->rd_att->attrs[varattno]->attname));
eref->colnames = lappend(eref->colnames, makeString(attrname));
rel = heap_open(funcrelid, AccessShareLock);
/*
* Since the rel is open anyway, let's check that the number of column
* aliases is reasonable.
*/
maxattrs = RelationGetNumberOfAttributes(rel);
if (maxattrs < numaliases)
elog(ERROR, "Table \"%s\" has %d columns available but %d columns specified",
RelationGetRelationName(rel), maxattrs, numaliases);
/* fill in alias columns using actual column names */
for (varattno = numaliases; varattno < maxattrs; varattno++)
{
char *attrname;
attrname = pstrdup(NameStr(rel->rd_att->attrs[varattno]->attname));
eref->colnames = lappend(eref->colnames, makeString(attrname));
}
/*
* Drop the rel refcount, but keep the access lock till end of
* transaction so that the table can't be deleted or have its schema
* modified underneath us.
*/
heap_close(rel, NoLock);
}
/*
* Drop the rel refcount, but keep the access lock till end of
* transaction so that the table can't be deleted or have its schema
* modified underneath us.
*/
heap_close(rel, NoLock);
else
elog(ERROR, "Invalid return relation specified for function %s",
funcname);
}
else
else if (functyptype == 'b')
{
/*
* Must be a base data type, i.e. scalar.
@ -776,6 +788,22 @@ addRangeTableEntryForFunction(ParseState *pstate,
if (numaliases == 0)
eref->colnames = makeList1(makeString(funcname));
}
else if (functyptype == 'p' && funcrettype == RECORDOID)
{
List *col;
foreach(col, coldeflist)
{
char *attrname;
ColumnDef *n = lfirst(col);
attrname = pstrdup(n->colname);
eref->colnames = lappend(eref->colnames, makeString(attrname));
}
}
else
elog(ERROR, "Unknown kind of return type specified for function %s",
funcname);
/*----------
* Flags:
@ -1051,56 +1079,70 @@ expandRTE(ParseState *pstate, RangeTblEntry *rte,
case RTE_FUNCTION:
{
/* Function RTE */
Oid funcrettype = exprType(rte->funcexpr);
Oid funcrelid = typeidTypeRelid(funcrettype);
Oid funcrettype = exprType(rte->funcexpr);
char functyptype = typeid_get_typtype(funcrettype);
List *coldeflist = rte->coldeflist;
if (OidIsValid(funcrelid))
/*
* Build a suitable tupledesc representing the output rows
*/
if (functyptype == 'c')
{
/*
* Composite data type, i.e. a table's row type
* Same as ordinary relation RTE
*/
Relation rel;
int maxattrs;
int numaliases;
rel = heap_open(funcrelid, AccessShareLock);
maxattrs = RelationGetNumberOfAttributes(rel);
numaliases = length(rte->eref->colnames);
for (varattno = 0; varattno < maxattrs; varattno++)
Oid funcrelid = typeidTypeRelid(funcrettype);
if (OidIsValid(funcrelid))
{
Form_pg_attribute attr = rel->rd_att->attrs[varattno];
if (attr->attisdropped)
continue;
/*
* Composite data type, i.e. a table's row type
* Same as ordinary relation RTE
*/
Relation rel;
int maxattrs;
int numaliases;
if (colnames)
rel = heap_open(funcrelid, AccessShareLock);
maxattrs = RelationGetNumberOfAttributes(rel);
numaliases = length(rte->eref->colnames);
for (varattno = 0; varattno < maxattrs; varattno++)
{
char *label;
Form_pg_attribute attr = rel->rd_att->attrs[varattno];
if (varattno < numaliases)
label = strVal(nth(varattno, rte->eref->colnames));
else
label = NameStr(attr->attname);
*colnames = lappend(*colnames, makeString(pstrdup(label)));
if (attr->attisdropped)
continue;
if (colnames)
{
char *label;
if (varattno < numaliases)
label = strVal(nth(varattno, rte->eref->colnames));
else
label = NameStr(attr->attname);
*colnames = lappend(*colnames, makeString(pstrdup(label)));
}
if (colvars)
{
Var *varnode;
varnode = makeVar(rtindex,
attr->attnum,
attr->atttypid,
attr->atttypmod,
sublevels_up);
*colvars = lappend(*colvars, varnode);
}
}
if (colvars)
{
Var *varnode;
varnode = makeVar(rtindex, attr->attnum,
attr->atttypid, attr->atttypmod,
sublevels_up);
*colvars = lappend(*colvars, varnode);
}
heap_close(rel, AccessShareLock);
}
heap_close(rel, AccessShareLock);
else
elog(ERROR, "Invalid return relation specified"
" for function");
}
else
else if (functyptype == 'b')
{
/*
* Must be a base data type, i.e. scalar
@ -1120,6 +1162,47 @@ expandRTE(ParseState *pstate, RangeTblEntry *rte,
*colvars = lappend(*colvars, varnode);
}
}
else if (functyptype == 'p' && funcrettype == RECORDOID)
{
List *col;
int attnum = 0;
foreach(col, coldeflist)
{
ColumnDef *colDef = lfirst(col);
attnum++;
if (colnames)
{
char *attrname;
attrname = pstrdup(colDef->colname);
*colnames = lappend(*colnames, makeString(attrname));
}
if (colvars)
{
Var *varnode;
HeapTuple typeTuple;
Oid atttypid;
typeTuple = typenameType(colDef->typename);
atttypid = HeapTupleGetOid(typeTuple);
ReleaseSysCache(typeTuple);
varnode = makeVar(rtindex,
attnum,
atttypid,
-1,
sublevels_up);
*colvars = lappend(*colvars, varnode);
}
}
}
else
elog(ERROR, "Unknown kind of return type specified"
" for function");
}
break;
case RTE_JOIN:
@ -1308,40 +1391,52 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
case RTE_FUNCTION:
{
/* Function RTE */
Oid funcrettype = exprType(rte->funcexpr);
Oid funcrelid = typeidTypeRelid(funcrettype);
Oid funcrettype = exprType(rte->funcexpr);
char functyptype = typeid_get_typtype(funcrettype);
List *coldeflist = rte->coldeflist;
if (OidIsValid(funcrelid))
/*
* Build a suitable tupledesc representing the output rows
*/
if (functyptype == 'c')
{
/*
* Composite data type, i.e. a table's row type
* Same as ordinary relation RTE
*/
HeapTuple tp;
Form_pg_attribute att_tup;
Oid funcrelid = typeidTypeRelid(funcrettype);
tp = SearchSysCache(ATTNUM,
ObjectIdGetDatum(funcrelid),
Int16GetDatum(attnum),
0, 0);
/* this shouldn't happen... */
if (!HeapTupleIsValid(tp))
elog(ERROR, "Relation %s does not have attribute %d",
get_rel_name(funcrelid), attnum);
att_tup = (Form_pg_attribute) GETSTRUCT(tp);
/*
* If dropped column, pretend it ain't there. See notes
* in scanRTEForColumn.
*/
if (att_tup->attisdropped)
elog(ERROR, "Relation \"%s\" has no column \"%s\"",
get_rel_name(funcrelid),
NameStr(att_tup->attname));
*vartype = att_tup->atttypid;
*vartypmod = att_tup->atttypmod;
ReleaseSysCache(tp);
if (OidIsValid(funcrelid))
{
HeapTuple tp;
Form_pg_attribute att_tup;
tp = SearchSysCache(ATTNUM,
ObjectIdGetDatum(funcrelid),
Int16GetDatum(attnum),
0, 0);
/* this shouldn't happen... */
if (!HeapTupleIsValid(tp))
elog(ERROR, "Relation %s does not have attribute %d",
get_rel_name(funcrelid), attnum);
att_tup = (Form_pg_attribute) GETSTRUCT(tp);
/*
* If dropped column, pretend it ain't there. See notes
* in scanRTEForColumn.
*/
if (att_tup->attisdropped)
elog(ERROR, "Relation \"%s\" has no column \"%s\"",
get_rel_name(funcrelid),
NameStr(att_tup->attname));
*vartype = att_tup->atttypid;
*vartypmod = att_tup->atttypmod;
ReleaseSysCache(tp);
}
else
elog(ERROR, "Invalid return relation specified"
" for function");
}
else
else if (functyptype == 'b')
{
/*
* Must be a base data type, i.e. scalar
@ -1349,6 +1444,22 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
*vartype = funcrettype;
*vartypmod = -1;
}
else if (functyptype == 'p' && funcrettype == RECORDOID)
{
ColumnDef *colDef = nth(attnum - 1, coldeflist);
HeapTuple typeTuple;
Oid atttypid;
typeTuple = typenameType(colDef->typename);
atttypid = HeapTupleGetOid(typeTuple);
ReleaseSysCache(typeTuple);
*vartype = atttypid;
*vartypmod = -1;
}
else
elog(ERROR, "Unknown kind of return type specified"
" for function");
}
break;
case RTE_JOIN:
@ -1576,3 +1687,28 @@ warnAutoRange(ParseState *pstate, RangeVar *relation)
pstate->parentParseState != NULL ? " in subquery" : "",
relation->relname);
}
char
typeid_get_typtype(Oid typeid)
{
HeapTuple typeTuple;
Form_pg_type typeStruct;
char result;
/*
* determine if the function returns a simple, named composite,
* or anonymous composite type
*/
typeTuple = SearchSysCache(TYPEOID,
ObjectIdGetDatum(typeid),
0, 0, 0);
if (!HeapTupleIsValid(typeTuple))
elog(ERROR, "cache lookup for type %u failed", typeid);
typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);
result = typeStruct->typtype;
ReleaseSysCache(typeTuple);
return result;
}