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Further cleanup of array behavior. Slice assignments to arrays with

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varlena elements work now.  Allow assignment to previously-nonexistent
subscript position to extend array, but only for 1-D arrays and only
if adjacent to existing positions (could do more if we had a way to
represent nulls in arrays, but I don't want to tackle that now).
Arrange for assignment of NULL to an array element in UPDATE to be a
no-op, rather than setting the entire array to NULL as it used to.
(Throwing an error would be a reasonable alternative, but it's never
done that...)  Update regress test accordingly.
This commit is contained in:
Tom Lane
2000-07-23 01:36:05 +00:00
parent ef2a6b8b83
commit e4e6459c0f
4 changed files with 618 additions and 255 deletions
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61
src/backend/executor/execQual.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.75 2000/07/22 03:34:27 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.76 2000/07/23 01:35:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -64,18 +64,30 @@ static Datum ExecEvalVar(Var *variable, ExprContext *econtext, bool *isNull);
static Datum ExecMakeFunctionResult(Node *node, List *arguments,
ExprContext *econtext, bool *isNull, bool *isDone);
/*
/*----------
* ExecEvalArrayRef
*
* This function takes an ArrayRef and returns the extracted Datum
* if it's a simple reference, or the modified array value if it's
* an array assignment (read array element insertion).
* an array assignment (i.e., array element or slice insertion).
*
* NOTE: if we get a NULL result from a subexpression, we return NULL when
* it's an array reference, or the unmodified source array when it's an
* array assignment. This may seem peculiar, but if we return NULL (as was
* done in versions up through 7.0) then an assignment like
* UPDATE table SET arrayfield[4] = NULL
* will result in setting the whole array to NULL, which is certainly not
* very desirable. By returning the source array we make the assignment
* into a no-op, instead. (Eventually we need to redesign arrays so that
* individual elements can be NULL, but for now, let's try to protect users
* from shooting themselves in the foot.)
*
* NOTE: we deliberately refrain from applying DatumGetArrayTypeP() here,
* even though that might seem natural, because this code needs to support
* both varlena arrays and fixed-length array types. DatumGetArrayTypeP()
* only works for the varlena kind. The routines we call in arrayfuncs.c
* have to know the difference (that's what they need refattrlength for).
*----------
*/
static Datum
ExecEvalArrayRef(ArrayRef *arrayRef,
@ -85,6 +97,7 @@ ExecEvalArrayRef(ArrayRef *arrayRef,
{
ArrayType *array_source;
ArrayType *resultArray;
bool isAssignment = (arrayRef->refassgnexpr != NULL);
List *elt;
int i = 0,
j = 0;
@ -102,7 +115,11 @@ ExecEvalArrayRef(ArrayRef *arrayRef,
econtext,
isNull,
isDone));
/* If refexpr yields NULL, result is always NULL, for now anyway */
/*
* If refexpr yields NULL, result is always NULL, for now anyway.
* (This means you cannot assign to an element or slice of an array
* that's NULL; it'll just stay NULL.)
*/
if (*isNull)
return (Datum) NULL;
}
@ -110,7 +127,7 @@ ExecEvalArrayRef(ArrayRef *arrayRef,
{
/*
* Null refexpr indicates we are doing an INSERT into an array
* Empty refexpr indicates we are doing an INSERT into an array
* column. For now, we just take the refassgnexpr (which the
* parser will have ensured is an array value) and return it
* as-is, ignoring any subscripts that may have been supplied in
@ -130,9 +147,14 @@ ExecEvalArrayRef(ArrayRef *arrayRef,
econtext,
isNull,
&dummy));
/* If any index expr yields NULL, result is NULL */
/* If any index expr yields NULL, result is NULL or source array */
if (*isNull)
return (Datum) NULL;
{
if (! isAssignment || array_source == NULL)
return (Datum) NULL;
*isNull = false;
return PointerGetDatum(array_source);
}
}
if (arrayRef->reflowerindexpr != NIL)
@ -147,9 +169,14 @@ ExecEvalArrayRef(ArrayRef *arrayRef,
econtext,
isNull,
&dummy));
/* If any index expr yields NULL, result is NULL */
/* If any index expr yields NULL, result is NULL or source array */
if (*isNull)
return (Datum) NULL;
{
if (! isAssignment || array_source == NULL)
return (Datum) NULL;
*isNull = false;
return PointerGetDatum(array_source);
}
}
if (i != j)
elog(ERROR,
@ -159,18 +186,26 @@ ExecEvalArrayRef(ArrayRef *arrayRef,
else
lIndex = NULL;
if (arrayRef->refassgnexpr != NULL)
if (isAssignment)
{
Datum sourceData = ExecEvalExpr(arrayRef->refassgnexpr,
econtext,
isNull,
&dummy);
/* For now, can't cope with inserting NULL into an array */
/*
* For now, can't cope with inserting NULL into an array,
* so make it a no-op per discussion above...
*/
if (*isNull)
return (Datum) NULL;
{
if (array_source == NULL)
return (Datum) NULL;
*isNull = false;
return PointerGetDatum(array_source);
}
if (array_source == NULL)
return sourceData; /* XXX do something else? */
return sourceData; /* XXX do something else? */
if (lIndex == NULL)
resultArray = array_set(array_source, i,