@ -106,7 +106,7 @@ static Node *transformCaseExpr(ParseState *pstate, CaseExpr *c);
static Node * transformSubLink ( ParseState * pstate , SubLink * sublink ) ;
static Node * transformArrayExpr ( ParseState * pstate , A_ArrayExpr * a ,
Oid array_type , Oid element_type , int32 typmod ) ;
static Node * transformRowExpr ( ParseState * pstate , RowExpr * r ) ;
static Node * transformRowExpr ( ParseState * pstate , RowExpr * r , bool allowDefault ) ;
static Node * transformCoalesceExpr ( ParseState * pstate , CoalesceExpr * c ) ;
static Node * transformMinMaxExpr ( ParseState * pstate , MinMaxExpr * m ) ;
static Node * transformSQLValueFunction ( ParseState * pstate ,
@ -299,7 +299,7 @@ transformExprRecurse(ParseState *pstate, Node *expr)
break ;
case T_RowExpr :
result = transformRowExpr ( pstate , ( RowExpr * ) expr ) ;
result = transformRowExpr ( pstate , ( RowExpr * ) expr , false ) ;
break ;
case T_CoalesceExpr :
@ -348,8 +348,20 @@ transformExprRecurse(ParseState *pstate, Node *expr)
break ;
/*
* CaseTestExpr and SetToDefault don ' t require any processing ;
* they are only injected into parse trees in fully - formed state .
* In all places where DEFAULT is legal , the caller should have
* processed it rather than passing it to transformExpr ( ) .
*/
case T_SetToDefault :
ereport ( ERROR ,
( errcode ( ERRCODE_SYNTAX_ERROR ) ,
errmsg ( " DEFAULT is not allowed in this context " ) ,
parser_errposition ( pstate ,
( ( SetToDefault * ) expr ) - > location ) ) ) ;
break ;
/*
* CaseTestExpr doesn ' t require any processing ; it is only
* injected into parse trees in a fully - formed state .
*
* Ordinarily we should not see a Var here , but it is convenient
* for transformJoinUsingClause ( ) to create untransformed operator
@ -358,7 +370,6 @@ transformExprRecurse(ParseState *pstate, Node *expr)
* references , which seems expensively pointless . So allow it .
*/
case T_CaseTestExpr :
case T_SetToDefault :
case T_Var :
{
result = ( Node * ) expr ;
@ -1486,9 +1497,9 @@ static Node *
transformMultiAssignRef ( ParseState * pstate , MultiAssignRef * maref )
{
SubLink * sublink ;
RowExpr * rexpr ;
Query * qtree ;
TargetEntry * tle ;
Param * param ;
/* We should only see this in first-stage processing of UPDATE tlists */
Assert ( pstate - > p_expr_kind = = EXPR_KIND_UPDATE_SOURCE ) ;
@ -1496,64 +1507,139 @@ transformMultiAssignRef(ParseState *pstate, MultiAssignRef *maref)
/* We only need to transform the source if this is the first column */
if ( maref - > colno = = 1 )
{
sublink = ( SubLink * ) transformExprRecurse ( pstate , maref - > source ) ;
/* Currently, the grammar only allows a SubLink as source */
Assert ( IsA ( sublink , SubLink ) ) ;
Assert ( sublink - > subLinkType = = MULTIEXPR_SUBLINK ) ;
qtree = ( Query * ) sublink - > subselect ;
Assert ( IsA ( qtree , Query ) ) ;
/* Check subquery returns required number of columns */
if ( count_nonjunk_tlist_entries ( qtree - > targetList ) ! = maref - > ncolumns )
ereport ( ERROR ,
( errcode ( ERRCODE_SYNTAX_ERROR ) ,
errmsg ( " number of columns does not match number of values " ) ,
parser_errposition ( pstate , sublink - > location ) ) ) ;
/*
* Build a resjunk tlist item containing the MULTIEXPR SubLink , and
* add it to pstate - > p_multiassign_exprs , whence it will later get
* appended to the completed targetlist . We needn ' t worry about
* selecting a resno for it ; transformUpdateStmt will do that .
* For now , we only allow EXPR SubLinks and RowExprs as the source of
* an UPDATE multiassignment . This is sufficient to cover interesting
* cases ; at worst , someone would have to write ( SELECT * FROM expr )
* to expand a composite - returning expression of another form .
*/
tle = makeTargetEntry ( ( Expr * ) sublink , 0 , NULL , true ) ;
pstate - > p_multiassign_exprs = lappend ( pstate - > p_multiassign_exprs , tle ) ;
if ( IsA ( maref - > source , SubLink ) & &
( ( SubLink * ) maref - > source ) - > subLinkType = = EXPR_SUBLINK )
{
/* Relabel it as a MULTIEXPR_SUBLINK */
sublink = ( SubLink * ) maref - > source ;
sublink - > subLinkType = MULTIEXPR_SUBLINK ;
/* And transform it */
sublink = ( SubLink * ) transformExprRecurse ( pstate ,
( Node * ) sublink ) ;
qtree = ( Query * ) sublink - > subselect ;
Assert ( IsA ( qtree , Query ) ) ;
/* Check subquery returns required number of columns */
if ( count_nonjunk_tlist_entries ( qtree - > targetList ) ! = maref - > ncolumns )
ereport ( ERROR ,
( errcode ( ERRCODE_SYNTAX_ERROR ) ,
errmsg ( " number of columns does not match number of values " ) ,
parser_errposition ( pstate , sublink - > location ) ) ) ;
/*
* Assign a unique - within - this - targetlist ID to the MULTIEXPR SubLink .
* We can just use its position in the p_multiassign_exprs list .
*/
sublink - > subLinkId = list_length ( pstate - > p_multiassign_exprs ) ;
/*
* Build a resjunk tlist item containing the MULTIEXPR SubLink ,
* and add it to pstate - > p_multiassign_exprs , whence it will later
* get appended to the completed targetlist . We needn ' t worry
* about selecting a resno for it ; transformUpdateStmt will do
* that .
*/
tle = makeTargetEntry ( ( Expr * ) sublink , 0 , NULL , true ) ;
pstate - > p_multiassign_exprs = lappend ( pstate - > p_multiassign_exprs ,
tle ) ;
/*
* Assign a unique - within - this - targetlist ID to the MULTIEXPR
* SubLink . We can just use its position in the
* p_multiassign_exprs list .
*/
sublink - > subLinkId = list_length ( pstate - > p_multiassign_exprs ) ;
}
else if ( IsA ( maref - > source , RowExpr ) )
{
/* Transform the RowExpr, allowing SetToDefault items */
rexpr = ( RowExpr * ) transformRowExpr ( pstate ,
( RowExpr * ) maref - > source ,
true ) ;
/* Check it returns required number of columns */
if ( list_length ( rexpr - > args ) ! = maref - > ncolumns )
ereport ( ERROR ,
( errcode ( ERRCODE_SYNTAX_ERROR ) ,
errmsg ( " number of columns does not match number of values " ) ,
parser_errposition ( pstate , rexpr - > location ) ) ) ;
/*
* Temporarily append it to p_multiassign_exprs , so we can get it
* back when we come back here for additional columns .
*/
tle = makeTargetEntry ( ( Expr * ) rexpr , 0 , NULL , true ) ;
pstate - > p_multiassign_exprs = lappend ( pstate - > p_multiassign_exprs ,
tle ) ;
}
else
ereport ( ERROR ,
( errcode ( ERRCODE_FEATURE_NOT_SUPPORTED ) ,
errmsg ( " source for a multiple-column UPDATE item must be a sub-SELECT or ROW() expression " ) ,
parser_errposition ( pstate , exprLocation ( maref - > source ) ) ) ) ;
}
else
{
/*
* Second or later column in a multiassignment . Re - fetch the
* transformed query , which we assume is still the last entry in
* p_multiassign_exprs .
* transformed SubLink or RowExpr , which we assume is still the last
* entry in p_multiassign_exprs .
*/
Assert ( pstate - > p_multiassign_exprs ! = NIL ) ;
tle = ( TargetEntry * ) llast ( pstate - > p_multiassign_exprs ) ;
}
/*
* Emit the appropriate output expression for the current column
*/
if ( IsA ( tle - > expr , SubLink ) )
{
Param * param ;
sublink = ( SubLink * ) tle - > expr ;
Assert ( IsA ( sublink , SubLink ) ) ;
Assert ( sublink - > subLinkType = = MULTIEXPR_SUBLINK ) ;
qtree = ( Query * ) sublink - > subselect ;
Assert ( IsA ( qtree , Query ) ) ;
/* Build a Param representing the current subquery output column */
tle = ( TargetEntry * ) list_nth ( qtree - > targetList , maref - > colno - 1 ) ;
Assert ( ! tle - > resjunk ) ;
param = makeNode ( Param ) ;
param - > paramkind = PARAM_MULTIEXPR ;
param - > paramid = ( sublink - > subLinkId < < 16 ) | maref - > colno ;
param - > paramtype = exprType ( ( Node * ) tle - > expr ) ;
param - > paramtypmod = exprTypmod ( ( Node * ) tle - > expr ) ;
param - > paramcollid = exprCollation ( ( Node * ) tle - > expr ) ;
param - > location = exprLocation ( ( Node * ) tle - > expr ) ;
return ( Node * ) param ;
}
/* Build a Param representing the appropriate subquery output column */
tle = ( TargetEntry * ) list_nth ( qtree - > targetList , maref - > colno - 1 ) ;
Assert ( ! tle - > resjunk ) ;
if ( IsA ( tle - > expr , RowExpr ) )
{
Node * result ;
rexpr = ( RowExpr * ) tle - > expr ;
param = makeNode ( Param ) ;
param - > paramkind = PARAM_MULTIEXPR ;
param - > paramid = ( sublink - > subLinkId < < 16 ) | maref - > colno ;
param - > paramtype = exprType ( ( Node * ) tle - > expr ) ;
param - > paramtypmod = exprTypmod ( ( Node * ) tle - > expr ) ;
param - > paramcollid = exprCollation ( ( Node * ) tle - > expr ) ;
param - > location = exprLocation ( ( Node * ) tle - > expr ) ;
/* Just extract and return the next element of the RowExpr */
result = ( Node * ) list_nth ( rexpr - > args , maref - > colno - 1 ) ;
/*
* If we ' re at the last column , delete the RowExpr from
* p_multiassign_exprs ; we don ' t need it anymore , and don ' t want it in
* the finished UPDATE tlist .
*/
if ( maref - > colno = = maref - > ncolumns )
pstate - > p_multiassign_exprs =
list_delete_ptr ( pstate - > p_multiassign_exprs , tle ) ;
return result ;
}
return ( Node * ) param ;
elog ( ERROR , " unexpected expr type in multiassign list " ) ;
return NULL ; /* keep compiler quiet */
}
static Node *
@ -2081,7 +2167,7 @@ transformArrayExpr(ParseState *pstate, A_ArrayExpr *a,
}
static Node *
transformRowExpr ( ParseState * pstate , RowExpr * r )
transformRowExpr ( ParseState * pstate , RowExpr * r , bool allowDefault )
{
RowExpr * newr ;
char fname [ 16 ] ;
@ -2091,7 +2177,8 @@ transformRowExpr(ParseState *pstate, RowExpr *r)
newr = makeNode ( RowExpr ) ;
/* Transform the field expressions */
newr - > args = transformExpressionList ( pstate , r - > args , pstate - > p_expr_kind ) ;
newr - > args = transformExpressionList ( pstate , r - > args ,
pstate - > p_expr_kind , allowDefault ) ;
/* Barring later casting, we consider the type RECORD */
newr - > row_typeid = RECORDOID ;
Tom Lane
9 years ago