/*
* create_tl_element--
* Creates a target list entry node and its associated (resdom var) pair
* with its resdom number equal to 'resdomno' and the joinlist field set
* to 'joinlist'.
*
* RETURNS: newly created tlist-entry
* CREATES: new targetlist entry (always).
*/
TargetEntry*
create_tl_element(Var *var, int resdomno)
{
TargetEntry *tlelement= makeNode(TargetEntry);
tlelement->resdom =
makeResdom(resdomno,
var->vartype,
get_typlen(var->vartype),
NULL,
(Index)0,
(Oid)0,
0);
tlelement->expr = (Node*)var;
return(tlelement);
}
/*
* Generate targetlist for a set-operation plan node
*
* colTypes: column datatypes for non-junk columns
* flag: -1 if no flag column needed, 0 or 1 to create a const flag column
* hack_constants: true to copy up constants (see comments in code)
* input_tlist: targetlist of this node's input node
* refnames_tlist: targetlist to take column names from
*/
static List *
generate_setop_tlist(List *colTypes, int flag,
bool hack_constants,
List *input_tlist,
List *refnames_tlist)
{
List *tlist = NIL;
int resno = 1;
List *i;
Resdom *resdom;
Node *expr;
foreach(i, colTypes)
{
Oid colType = lfirsto(i);
TargetEntry *inputtle = (TargetEntry *) lfirst(input_tlist);
TargetEntry *reftle = (TargetEntry *) lfirst(refnames_tlist);
int32 colTypmod;
Assert(inputtle->resdom->resno == resno);
Assert(reftle->resdom->resno == resno);
Assert(!inputtle->resdom->resjunk);
Assert(!reftle->resdom->resjunk);
/*
* Generate columns referencing input columns and having
* appropriate data types and column names. Insert datatype
* coercions where necessary.
*
* HACK: constants in the input's targetlist are copied up as-is
* rather than being referenced as subquery outputs. This is
* mainly to ensure that when we try to coerce them to the output
* column's datatype, the right things happen for UNKNOWN
* constants. But do this only at the first level of
* subquery-scan plans; we don't want phony constants appearing in
* the output tlists of upper-level nodes!
*/
if (hack_constants && inputtle->expr && IsA(inputtle->expr, Const))
expr = (Node *) inputtle->expr;
else
expr = (Node *) makeVar(0,
inputtle->resdom->resno,
inputtle->resdom->restype,
inputtle->resdom->restypmod,
0);
if (inputtle->resdom->restype == colType)
{
/* no coercion needed, and believe the input typmod */
colTypmod = inputtle->resdom->restypmod;
}
else
{
expr = coerce_to_common_type(NULL, /* no UNKNOWNs here */
expr,
colType,
"UNION/INTERSECT/EXCEPT");
colTypmod = -1;
}
resdom = makeResdom((AttrNumber) resno++,
colType,
colTypmod,
pstrdup(reftle->resdom->resname),
false);
tlist = lappend(tlist, makeTargetEntry(resdom, (Expr *) expr));
input_tlist = lnext(input_tlist);
refnames_tlist = lnext(refnames_tlist);
}