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Commitbedd04a

Browse files
author
Thomas G. Lockhart
committed
Implement CASE expression.
1 parent19740e2 commitbedd04a

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17 files changed

+777
-108
lines changed

17 files changed

+777
-108
lines changed

‎src/backend/executor/execQual.c‎

Lines changed: 83 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.38 1998/11/27 19:52:00 vadim Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.39 1998/12/04 15:33:19 thomas Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -20,7 +20,7 @@
2020
* NOTES
2121
*ExecEvalExpr() and ExecEvalVar() are hotspots.making these faster
2222
*will speed up the entire system. Unfortunately they are currently
23-
*implemented recursively.. Eliminating the recursion is bound to
23+
*implemented recursively. Eliminating the recursion is bound to
2424
*improve the speed of the executor.
2525
*
2626
*ExecTargetList() is used to make tuple projections. Rather then
@@ -205,7 +205,7 @@ ExecEvalAggreg(Aggreg *agg, ExprContext *econtext, bool *isNull)
205205
*variable with respect to given expression context.
206206
*
207207
*
208-
*As an entry condition, we expect that thethedatatype the
208+
*As an entry condition, we expect that the datatype the
209209
*plan expects to get (as told by our "variable" argument) is in
210210
*fact the datatype of the attribute the plan says to fetch (as
211211
*seen in the current context, identified by our "econtext"
@@ -1124,6 +1124,79 @@ ExecEvalAnd(Expr *andExpr, ExprContext *econtext, bool *isNull)
11241124
returnconst_value;
11251125
}
11261126

1127+
/* ----------------------------------------------------------------
1128+
*ExecEvalCase
1129+
*
1130+
*Evaluate a CASE clause. Will have boolean expressions
1131+
*inside the WHEN clauses, and will have constants
1132+
*for results.
1133+
*- thomas 1998-11-09
1134+
* ----------------------------------------------------------------
1135+
*/
1136+
staticDatum
1137+
ExecEvalCase(CaseExpr*caseExpr,ExprContext*econtext,bool*isNull)
1138+
{
1139+
List*clauses;
1140+
List*clause;
1141+
CaseWhen*wclause;
1142+
Datumconst_value=0;
1143+
boolisDone;
1144+
1145+
clauses=caseExpr->args;
1146+
1147+
/******************
1148+
*we evaluate each of the WHEN clauses in turn,
1149+
*as soon as one is true we return the corresponding
1150+
*result.If none are true then we return the value
1151+
*of the default clause, or NULL.
1152+
******************
1153+
*/
1154+
foreach(clause,clauses)
1155+
{
1156+
1157+
/******************
1158+
*We don't iterate over sets in the quals, so pass in an isDone
1159+
*flag, but ignore it.
1160+
******************
1161+
*/
1162+
1163+
wclause=lfirst(clause);
1164+
const_value=ExecEvalExpr((Node*)wclause->expr,
1165+
econtext,
1166+
isNull,
1167+
&isDone);
1168+
1169+
/******************
1170+
* if we have a true test, then we return the result,
1171+
* since the case statement is satisfied.
1172+
******************
1173+
*/
1174+
if (DatumGetInt32(const_value)!=0)
1175+
{
1176+
const_value=ExecEvalExpr((Node*)wclause->result,
1177+
econtext,
1178+
isNull,
1179+
&isDone);
1180+
return (Datum)const_value;
1181+
1182+
}
1183+
}
1184+
1185+
if (caseExpr->defresult)
1186+
{
1187+
const_value=ExecEvalExpr((Node*)caseExpr->defresult,
1188+
econtext,
1189+
isNull,
1190+
&isDone);
1191+
}
1192+
else
1193+
{
1194+
*isNull= true;
1195+
}
1196+
1197+
returnconst_value;
1198+
}
1199+
11271200
/* ----------------------------------------------------------------
11281201
*ExecEvalExpr
11291202
*
@@ -1236,13 +1309,18 @@ ExecEvalExpr(Node *expression,
12361309
}
12371310
break;
12381311
}
1312+
caseT_CaseExpr:
1313+
retDatum= (Datum)ExecEvalCase((CaseExpr*)expression,econtext,isNull);
1314+
break;
1315+
12391316
default:
12401317
elog(ERROR,"ExecEvalExpr: unknown expression type %d",nodeTag(expression));
12411318
break;
12421319
}
12431320

12441321
returnretDatum;
1245-
}
1322+
}/* ExecEvalExpr() */
1323+
12461324

12471325
/* ----------------------------------------------------------------
12481326
* ExecQual / ExecTargetList
@@ -1642,3 +1720,4 @@ ExecProject(ProjectionInfo *projInfo, bool *isDone)
16421720
InvalidBuffer,/* tuple has no buffer */
16431721
true);
16441722
}
1723+

‎src/backend/nodes/copyfuncs.c‎

Lines changed: 48 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.50 1998/11/22 10:48:38 vadim Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.51 1998/12/04 15:33:33 thomas Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -943,6 +943,47 @@ _copySubLink(SubLink *from)
943943
returnnewnode;
944944
}
945945

946+
/* ----------------
947+
*_copyCaseExpr
948+
* ----------------
949+
*/
950+
staticCaseExpr*
951+
_copyCaseExpr(CaseExpr*from)
952+
{
953+
CaseExpr*newnode=makeNode(CaseExpr);
954+
955+
/* ----------------
956+
*copy remainder of node
957+
* ----------------
958+
*/
959+
newnode->casetype=from->casetype;
960+
961+
Node_Copy(from,newnode,arg);
962+
Node_Copy(from,newnode,args);
963+
Node_Copy(from,newnode,defresult);
964+
965+
returnnewnode;
966+
}
967+
968+
/* ----------------
969+
*_copyCaseWhen
970+
* ----------------
971+
*/
972+
staticCaseWhen*
973+
_copyCaseWhen(CaseWhen*from)
974+
{
975+
CaseWhen*newnode=makeNode(CaseWhen);
976+
977+
/* ----------------
978+
*copy remainder of node
979+
* ----------------
980+
*/
981+
Node_Copy(from,newnode,expr);
982+
Node_Copy(from,newnode,result);
983+
984+
returnnewnode;
985+
}
986+
946987
staticArray*
947988
_copyArray(Array*from)
948989
{
@@ -1734,6 +1775,12 @@ copyObject(void *from)
17341775
caseT_SubLink:
17351776
retval=_copySubLink(from);
17361777
break;
1778+
caseT_CaseExpr:
1779+
retval=_copyCaseExpr(from);
1780+
break;
1781+
caseT_CaseWhen:
1782+
retval=_copyCaseWhen(from);
1783+
break;
17371784

17381785
/*
17391786
* RELATION NODES

‎src/backend/nodes/outfuncs.c‎

Lines changed: 86 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.48 1998/11/22 10:48:39 vadim Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.49 1998/12/04 15:33:33 thomas Exp $
1111
*
1212
* NOTES
1313
* Every (plan) node in POSTGRES has an associated "out" routine which
@@ -1635,6 +1635,82 @@ _outAConst(StringInfo str, A_Const *node)
16351635
return;
16361636
}
16371637

1638+
staticvoid
1639+
_outConstraint(StringInfostr,Constraint*node)
1640+
{
1641+
charbuf[500];
1642+
1643+
sprintf(buf," %s :type",
1644+
((node->name!=NULL)?node->name:"<>"));
1645+
appendStringInfo(str,buf);
1646+
1647+
switch (node->contype)
1648+
{
1649+
caseCONSTR_PRIMARY:
1650+
sprintf(buf," PRIMARY KEY ");
1651+
appendStringInfo(str,buf);
1652+
_outNode(str,node->keys);
1653+
break;
1654+
1655+
caseCONSTR_CHECK:
1656+
sprintf(buf," CHECK ");
1657+
appendStringInfo(str,buf);
1658+
appendStringInfo(str,node->def);
1659+
break;
1660+
1661+
caseCONSTR_DEFAULT:
1662+
sprintf(buf," DEFAULT ");
1663+
appendStringInfo(str,buf);
1664+
appendStringInfo(str,node->def);
1665+
break;
1666+
1667+
caseCONSTR_NOTNULL:
1668+
sprintf(buf," NOT NULL ");
1669+
appendStringInfo(str,buf);
1670+
break;
1671+
1672+
caseCONSTR_UNIQUE:
1673+
sprintf(buf," UNIQUE ");
1674+
appendStringInfo(str,buf);
1675+
_outNode(str,node->keys);
1676+
break;
1677+
1678+
default:
1679+
sprintf(buf,"<unrecognized constraint>");
1680+
appendStringInfo(str,buf);
1681+
break;
1682+
}
1683+
return;
1684+
}
1685+
1686+
staticvoid
1687+
_outCaseExpr(StringInfostr,CaseExpr*node)
1688+
{
1689+
charbuf[500];
1690+
1691+
sprintf(buf,"CASE ");
1692+
appendStringInfo(str,buf);
1693+
_outNode(str,node->args);
1694+
sprintf(buf," :default ");
1695+
appendStringInfo(str,buf);
1696+
_outNode(str,node->defresult);
1697+
return;
1698+
}
1699+
1700+
staticvoid
1701+
_outCaseWhen(StringInfostr,CaseWhen*node)
1702+
{
1703+
charbuf[500];
1704+
1705+
sprintf(buf," :when ");
1706+
appendStringInfo(str,buf);
1707+
_outNode(str,node->expr);
1708+
sprintf(buf," :then ");
1709+
appendStringInfo(str,buf);
1710+
_outNode(str,node->result);
1711+
return;
1712+
}
1713+
16381714
/*
16391715
* _outNode -
16401716
* converts a Node into ascii string and append it to 'str'
@@ -1861,6 +1937,15 @@ _outNode(StringInfo str, void *obj)
18611937
caseT_A_Const:
18621938
_outAConst(str,obj);
18631939
break;
1940+
caseT_Constraint:
1941+
_outConstraint(str,obj);
1942+
break;
1943+
caseT_CaseExpr:
1944+
_outCaseExpr(str,obj);
1945+
break;
1946+
caseT_CaseWhen:
1947+
_outCaseWhen(str,obj);
1948+
break;
18641949
default:
18651950
elog(NOTICE,"_outNode: don't know how to print type %d ",
18661951
nodeTag(obj));

‎src/backend/optimizer/plan/createplan.c‎

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.33 1998/11/22 10:48:43 vadim Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.34 1998/12/04 15:34:05 thomas Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -437,7 +437,7 @@ create_nestloop_node(JoinPath *best_path,
437437
* used in the inner scan path, so we need only consider the first
438438
* set of qualifications in indxqual.
439439
*
440-
* But there may be more than oneclauses in this "first set" in the
440+
* But there may be more than oneclause in this "first set" in the
441441
* case of multi-column indices. - vadim 03/18/97
442442
*/
443443

@@ -735,6 +735,11 @@ fix_indxqual_references(Node *clause, Path *index_path)
735735
else
736736
returnclause;
737737
}
738+
elseif (IsA(clause,CaseExpr))
739+
{
740+
elog(NOTICE,"optimizer: fix_indxqual_references sees CaseExpr");
741+
returnclause;
742+
}
738743
else
739744
{
740745
List*oldclauses= (List*)clause;

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