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Implement CASE expression.

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This commit is contained in:
Thomas G. Lockhart
1998-12-04 15:34:49 +00:00
parent 19740e2fff
commit bedd04a551
17 changed files with 779 additions and 110 deletions
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41
src/backend/optimizer/util/clauses.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.25 1998/11/27 19:52:07 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.26 1998/12/04 15:34:14 thomas Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -306,6 +306,26 @@ make_andclause(List *andclauses)
return expr;
}
/*****************************************************************************
* CASE clause functions
*****************************************************************************/
/*
* case_clause--
*
* Returns t iff its argument is a 'case' clause: (CASE { expr }).
*
*/
bool
case_clause(Node *clause)
{
return
(clause != NULL &&
nodeTag(clause) == T_CaseExpr);
}
/*****************************************************************************
* *
* *
@@ -540,6 +560,19 @@ fix_opid(Node *clause)
fix_opid((Node *) get_leftop((Expr *) lfirst(lst)));
}
}
else if (case_clause(clause))
{
List *lst;
fix_opid(((CaseExpr *) clause)->defresult);
/* Run through the WHEN clauses... */
foreach(lst, ((CaseExpr *) clause)->args)
{
fix_opid(((CaseWhen *) lfirst(lst))->expr);
fix_opid(((CaseWhen *) lfirst(lst))->result);
}
}
}
@@ -577,13 +610,12 @@ fix_opids(List *clauses)
* returned for the value if it is unknown or null.
* END OF OLD OBSOLETE COMMENT.
* NEW COMMENT:
* when defining rules one of the attibutes of the operator can
* when defining rules one of the attributes of the operator can
* be a Param node (which is supposed to be treated as a constant).
* However as there is no value specified for a parameter until run time
* this routine used to return "" as value, which made 'compute_selec'
* this routine used to return "" as value, which caused 'compute_selec'
* to bomb (because it was expecting a lisp integer and got back a lisp
* string). Now the code returns a plain old good "lispInteger(0)".
*
*/
void
get_relattval(Node *clause,
@@ -787,3 +819,4 @@ CommuteClause(Node *clause)
lfirst(((Expr *) clause)->args) = lsecond(((Expr *) clause)->args);
lsecond(((Expr *) clause)->args) = temp;
}

34
src/backend/optimizer/util/tlist.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/tlist.c,v 1.20 1998/09/22 21:48:27 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/tlist.c,v 1.21 1998/12/04 15:34:15 thomas Exp $
*
*-------------------------------------------------------------------------
*/
@@ -482,7 +482,6 @@ flatten_tlistentry(Node *tlistentry, List *flat_tlist)
flatten_tlistentry(lfirst(elt), flat_tlist));
return ((Node *) make_funcclause((Func *) expr->oper, temp_result));
}
else if (IsA(tlistentry, Aggreg))
{
@@ -509,19 +508,36 @@ flatten_tlistentry(Node *tlistentry, List *flat_tlist)
return tlistentry;
}
else if (case_clause(tlistentry))
{
CaseExpr *cexpr = (CaseExpr *) tlistentry;
CaseWhen *cwhen;
List *elt = NIL;
foreach(elt, cexpr->args)
cwhen = (CaseWhen *)lfirst(elt);
cwhen->result = flatten_tlistentry(cwhen->result, flat_tlist);
cexpr->defresult = flatten_tlistentry(cexpr->defresult, flat_tlist);
return ((Node *) cexpr);
}
else
{
Expr *expr = (Expr *) tlistentry;
Var *left = (Var *) flatten_tlistentry((Node *) get_leftop(expr),
flat_tlist);
Var *right = (Var *) flatten_tlistentry((Node *) get_rightop(expr),
flat_tlist);
Expr *final = make_opclause((Oper *) expr->oper, left, right);
Expr *expr, *final;
Var *left, *right;
Assert(IsA(tlistentry, Expr));
expr = (Expr *) tlistentry;
left = (Var *) flatten_tlistentry((Node *) get_leftop(expr),
flat_tlist);
right = (Var *) flatten_tlistentry((Node *) get_rightop(expr),
flat_tlist);
final = make_opclause((Oper *) expr->oper, left, right);
final->opType = expr->opType;
final->typeOid = expr->typeOid;
return (Node *)final;
}
}

29
src/backend/optimizer/util/var.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.13 1998/09/01 03:24:00 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/var.c,v 1.14 1998/12/04 15:34:15 thomas Exp $
*
*-------------------------------------------------------------------------
*/
@@ -137,6 +137,21 @@ contain_var_clause(Node *clause)
else if (is_opclause(clause))
return (contain_var_clause((Node *) get_leftop((Expr *) clause)) ||
contain_var_clause((Node *) get_rightop((Expr *) clause)));
else if (case_clause(clause))
{
List *args;
CaseWhen *when;
foreach(args, ((CaseExpr *) clause)->args)
{
when = lfirst(args);
if (contain_var_clause(when->expr))
return TRUE;
if (contain_var_clause(when->result))
return TRUE;
}
return (contain_var_clause(((CaseExpr *) clause)->defresult));
}
return FALSE;
}
@@ -199,6 +214,18 @@ pull_var_clause(Node *clause)
else if (is_opclause(clause))
retval = nconc(pull_var_clause((Node *) get_leftop((Expr *) clause)),
pull_var_clause((Node *) get_rightop((Expr *) clause)));
else if (case_clause(clause))
{
List *temp;
foreach(temp, ((CaseExpr *) clause)->args)
{
retval = nconc(retval, pull_var_clause(((CaseWhen *) lfirst(temp))->expr));
retval = nconc(retval, pull_var_clause(((CaseWhen *) lfirst(temp))->result));
}
retval = nconc(retval, pull_var_clause(((CaseExpr *) clause)->defresult));
}
else
retval = NIL;