/*---------------------------------------------------------------------
* DefineVirtualRelation
*
* Create the "view" relation. `DefineRelation' does all the work,
* we just provide the correct arguments ... at least when we're
* creating a view. If we're updating an existing view, we have to
* work harder.
*---------------------------------------------------------------------
*/
static ObjectAddress
DefineVirtualRelation(RangeVar *relation, List *tlist, bool replace,
List *options)
{
Oid viewOid;
LOCKMODE lockmode;
CreateStmt *createStmt = makeNode(CreateStmt);
List *attrList;
ListCell *t;
/*
* create a list of ColumnDef nodes based on the names and types of the
* (non-junk) targetlist items from the view's SELECT list.
*/
attrList = NIL;
foreach(t, tlist)
{
TargetEntry *tle = lfirst(t);
if (!tle->resjunk)
{
ColumnDef *def = makeNode(ColumnDef);
def->colname = pstrdup(tle->resname);
def->typeName = makeTypeNameFromOid(exprType((Node *) tle->expr),
exprTypmod((Node *) tle->expr));
def->inhcount = 0;
def->is_local = true;
def->is_not_null = false;
def->is_from_type = false;
def->storage = 0;
def->raw_default = NULL;
def->cooked_default = NULL;
def->collClause = NULL;
def->collOid = exprCollation((Node *) tle->expr);
def->location = -1;
/*
* It's possible that the column is of a collatable type but the
* collation could not be resolved, so double-check.
*/
if (type_is_collatable(exprType((Node *) tle->expr)))
{
if (!OidIsValid(def->collOid))
ereport(ERROR,
(errcode(ERRCODE_INDETERMINATE_COLLATION),
errmsg("could not determine which collation to use for view column \"%s\"",
def->colname),
errhint("Use the COLLATE clause to set the collation explicitly.")));
}
else
Assert(!OidIsValid(def->collOid));
def->constraints = NIL;
attrList = lappend(attrList, def);
}
}
/*
* makeVarFromTargetEntry -
* convenience function to create a same-level Var node from a
* TargetEntry
*/
Var *
makeVarFromTargetEntry(Index varno,
TargetEntry *tle)
{
return makeVar(varno,
tle->resno,
exprType((Node *) tle->expr),
exprTypmod((Node *) tle->expr),
exprCollation((Node *) tle->expr),
0);
}
/*
* create_ctas_nodata
*
* Create CTAS or materialized view when WITH NO DATA is used, starting from
* the targetlist of the SELECT or view definition.
*/
static ObjectAddress
create_ctas_nodata(List *tlist, IntoClause *into)
{
List *attrList;
ListCell *t,
*lc;
/*
* Build list of ColumnDefs from non-junk elements of the tlist. If a
* column name list was specified in CREATE TABLE AS, override the column
* names in the query. (Too few column names are OK, too many are not.)
*/
attrList = NIL;
lc = list_head(into->colNames);
foreach(t, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(t);
if (!tle->resjunk)
{
ColumnDef *col;
char *colname;
if (lc)
{
colname = strVal(lfirst(lc));
lc = lnext(lc);
}
else
colname = tle->resname;
col = makeColumnDef(colname,
exprType((Node *) tle->expr),
exprTypmod((Node *) tle->expr),
exprCollation((Node *) tle->expr));
/*
* It's possible that the column is of a collatable type but the
* collation could not be resolved, so double-check. (We must
* check this here because DefineRelation would adopt the type's
* default collation rather than complaining.)
*/
if (!OidIsValid(col->collOid) &&
type_is_collatable(col->typeName->typeOid))
ereport(ERROR,
(errcode(ERRCODE_INDETERMINATE_COLLATION),
errmsg("no collation was derived for column \"%s\" with collatable type %s",
col->colname,
format_type_be(col->typeName->typeOid)),
errhint("Use the COLLATE clause to set the collation explicitly.")));
attrList = lappend(attrList, col);
}
}
/*---------------------------------------------------------------------
* DefineVirtualRelation
*
* Create a view relation and use the rules system to store the query
* for the view.
*---------------------------------------------------------------------
*/
static ObjectAddress
DefineVirtualRelation(RangeVar *relation, List *tlist, bool replace,
List *options, Query *viewParse)
{
Oid viewOid;
LOCKMODE lockmode;
CreateStmt *createStmt = makeNode(CreateStmt);
List *attrList;
ListCell *t;
/*
* create a list of ColumnDef nodes based on the names and types of the
* (non-junk) targetlist items from the view's SELECT list.
*/
attrList = NIL;
foreach(t, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(t);
if (!tle->resjunk)
{
ColumnDef *def = makeColumnDef(tle->resname,
exprType((Node *) tle->expr),
exprTypmod((Node *) tle->expr),
exprCollation((Node *) tle->expr));
/*
* It's possible that the column is of a collatable type but the
* collation could not be resolved, so double-check.
*/
if (type_is_collatable(exprType((Node *) tle->expr)))
{
if (!OidIsValid(def->collOid))
ereport(ERROR,
(errcode(ERRCODE_INDETERMINATE_COLLATION),
errmsg("could not determine which collation to use for view column \"%s\"",
def->colname),
errhint("Use the COLLATE clause to set the collation explicitly.")));
}
else
Assert(!OidIsValid(def->collOid));
attrList = lappend(attrList, def);
}
}
/*
* makeWholeRowVar -
* creates a Var node representing a whole row of the specified RTE
*
* A whole-row reference is a Var with varno set to the correct range
* table entry, and varattno == 0 to signal that it references the whole
* tuple. (Use of zero here is unclean, since it could easily be confused
* with error cases, but it's not worth changing now.) The vartype indicates
* a rowtype; either a named composite type, or RECORD. This function
* encapsulates the logic for determining the correct rowtype OID to use.
*
* If allowScalar is true, then for the case where the RTE is a function
* returning a non-composite result type, we produce a normal Var referencing
* the function's result directly, instead of the single-column composite
* value that the whole-row notation might otherwise suggest.
*/
Var *
makeWholeRowVar(RangeTblEntry *rte,
Index varno,
Index varlevelsup,
bool allowScalar)
{
Var *result;
Oid toid;
switch (rte->rtekind)
{
case RTE_RELATION:
/* relation: the rowtype is a named composite type */
toid = get_rel_type_id(rte->relid);
if (!OidIsValid(toid))
elog(ERROR, "could not find type OID for relation %u",
rte->relid);
result = makeVar(varno,
InvalidAttrNumber,
toid,
-1,
InvalidOid,
varlevelsup);
break;
case RTE_FUNCTION:
toid = exprType(rte->funcexpr);
if (type_is_rowtype(toid))
{
/* func returns composite; same as relation case */
result = makeVar(varno,
InvalidAttrNumber,
toid,
-1,
InvalidOid,
varlevelsup);
}
else if (allowScalar)
{
/* func returns scalar; just return its output as-is */
result = makeVar(varno,
1,
toid,
-1,
exprCollation(rte->funcexpr),
varlevelsup);
}
else
{
/* func returns scalar, but we want a composite result */
result = makeVar(varno,
InvalidAttrNumber,
RECORDOID,
-1,
InvalidOid,
varlevelsup);
}
break;
default:
/*
* RTE is a join, subselect, or VALUES. We represent this as a
* whole-row Var of RECORD type. (Note that in most cases the Var
* will be expanded to a RowExpr during planning, but that is not
* our concern here.)
*/
result = makeVar(varno,
InvalidAttrNumber,
RECORDOID,
-1,
InvalidOid,
varlevelsup);
break;
}
return result;
}
/*
* makeWholeRowVar -
* creates a Var node representing a whole row of the specified RTE
*
* A whole-row reference is a Var with varno set to the correct range
* table entry, and varattno == 0 to signal that it references the whole
* tuple. (Use of zero here is unclean, since it could easily be confused
* with error cases, but it's not worth changing now.) The vartype indicates
* a rowtype; either a named composite type, or RECORD. This function
* encapsulates the logic for determining the correct rowtype OID to use.
*
* If allowScalar is true, then for the case where the RTE is a single function
* returning a non-composite result type, we produce a normal Var referencing
* the function's result directly, instead of the single-column composite
* value that the whole-row notation might otherwise suggest.
*/
Var *
makeWholeRowVar(RangeTblEntry *rte,
Index varno,
Index varlevelsup,
bool allowScalar)
{
Var *result;
Oid toid;
Node *fexpr;
switch (rte->rtekind)
{
case RTE_RELATION:
/* relation: the rowtype is a named composite type */
toid = get_rel_type_id(rte->relid);
if (!OidIsValid(toid))
elog(ERROR, "could not find type OID for relation %u",
rte->relid);
result = makeVar(varno,
InvalidAttrNumber,
toid,
-1,
InvalidOid,
varlevelsup);
break;
case RTE_FUNCTION:
/*
* If there's more than one function, or ordinality is requested,
* force a RECORD result, since there's certainly more than one
* column involved and it can't be a known named type.
*/
if (rte->funcordinality || list_length(rte->functions) != 1)
{
/* always produces an anonymous RECORD result */
result = makeVar(varno,
InvalidAttrNumber,
RECORDOID,
-1,
InvalidOid,
varlevelsup);
break;
}
fexpr = ((RangeTblFunction *) linitial(rte->functions))->funcexpr;
toid = exprType(fexpr);
if (type_is_rowtype(toid))
{
/* func returns composite; same as relation case */
result = makeVar(varno,
InvalidAttrNumber,
toid,
-1,
InvalidOid,
varlevelsup);
}
else if (allowScalar)
{
/* func returns scalar; just return its output as-is */
result = makeVar(varno,
1,
toid,
-1,
exprCollation(fexpr),
varlevelsup);
}
else
{
/* func returns scalar, but we want a composite result */
result = makeVar(varno,
InvalidAttrNumber,
RECORDOID,
-1,
InvalidOid,
varlevelsup);
}
break;
default:
/*
* RTE is a join, subselect, or VALUES. We represent this as a
* whole-row Var of RECORD type. (Note that in most cases the Var
* will be expanded to a RowExpr during planning, but that is not
* our concern here.)
*/
result = makeVar(varno,
InvalidAttrNumber,
RECORDOID,
-1,
InvalidOid,
varlevelsup);
break;
}
return result;
}
/* ----------------------------------------------------------------
* ExecInitFunctionScan
* ----------------------------------------------------------------
*/
FunctionScanState *
ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
{
FunctionScanState *scanstate;
Oid funcrettype;
TypeFuncClass functypclass;
TupleDesc tupdesc = NULL;
/* check for unsupported flags */
Assert(!(eflags & EXEC_FLAG_MARK));
/*
* FunctionScan should not have any children.
*/
Assert(outerPlan(node) == NULL);
Assert(innerPlan(node) == NULL);
/*
* create new ScanState for node
*/
scanstate = makeNode(FunctionScanState);
scanstate->ss.ps.plan = (Plan *) node;
scanstate->ss.ps.state = estate;
scanstate->eflags = eflags;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &scanstate->ss.ps);
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
ExecInitScanTupleSlot(estate, &scanstate->ss);
/*
* initialize child expressions
*/
scanstate->ss.ps.targetlist = (List *)
ExecInitExpr((Expr *) node->scan.plan.targetlist,
(PlanState *) scanstate);
scanstate->ss.ps.qual = (List *)
ExecInitExpr((Expr *) node->scan.plan.qual,
(PlanState *) scanstate);
/*
* Now determine if the function returns a simple or composite type, and
* build an appropriate tupdesc.
*/
functypclass = get_expr_result_type(node->funcexpr,
&funcrettype,
&tupdesc);
if (functypclass == TYPEFUNC_COMPOSITE)
{
/* Composite data type, e.g. a table's row type */
Assert(tupdesc);
/* Must copy it out of typcache for safety */
tupdesc = CreateTupleDescCopy(tupdesc);
}
else if (functypclass == TYPEFUNC_SCALAR)
{
/* Base data type, i.e. scalar */
char *attname = strVal(linitial(node->funccolnames));
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
attname,
funcrettype,
-1,
0);
TupleDescInitEntryCollation(tupdesc,
(AttrNumber) 1,
exprCollation(node->funcexpr));
}
else if (functypclass == TYPEFUNC_RECORD)
{
tupdesc = BuildDescFromLists(node->funccolnames,
node->funccoltypes,
node->funccoltypmods,
node->funccolcollations);
}
else
{
/* crummy error message, but parser should have caught this */
elog(ERROR, "function in FROM has unsupported return type");
}
/*
* For RECORD results, make sure a typmod has been assigned. (The
* function should do this for itself, but let's cover things in case it
* doesn't.)
*/
BlessTupleDesc(tupdesc);
scanstate->tupdesc = tupdesc;
ExecAssignScanType(&scanstate->ss, tupdesc);
/*
* Other node-specific setup
*/
scanstate->tuplestorestate = NULL;
scanstate->funcexpr = ExecInitExpr((Expr *) node->funcexpr,
(PlanState *) scanstate);
scanstate->ss.ps.ps_TupFromTlist = false;
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&scanstate->ss.ps);
ExecAssignScanProjectionInfo(&scanstate->ss);
return scanstate;
}
