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https://github.com/postgres/postgres.git
synced 2025-06-14 18:42:34 +03:00
Support assignment to subfields of composite columns in UPDATE and INSERT.
As a side effect, cause subscripts in INSERT targetlists to do something more or less sensible; previously we evaluated such subscripts and then effectively ignored them. Another side effect is that UPDATE-ing an element or slice of an array value that is NULL now produces a non-null result, namely an array containing just the assigned-to positions.
This commit is contained in:
Tom Lane
@ -3,7 +3,7 @@
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* back to source text
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.170 2004/06/06 00:41:27 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.171 2004/06/09 19:08:18 tgl Exp $
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*
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* This software is copyrighted by Jan Wieck - Hamburg.
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*
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@ -204,7 +204,8 @@ static void get_from_clause_coldeflist(List *coldeflist,
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deparse_context *context);
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static void get_opclass_name(Oid opclass, Oid actual_datatype,
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StringInfo buf);
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static bool tleIsArrayAssign(TargetEntry *tle);
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static Node *processIndirection(Node *node, deparse_context *context);
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static void printSubscripts(ArrayRef *aref, deparse_context *context);
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static char *generate_relation_name(Oid relid);
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static char *generate_function_name(Oid funcid, int nargs, Oid *argtypes);
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static char *generate_operator_name(Oid operid, Oid arg1, Oid arg2);
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@ -2061,6 +2062,7 @@ get_insert_query_def(Query *query, deparse_context *context)
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RangeTblEntry *rte;
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char *sep;
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ListCell *l;
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List *strippedexprs;
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/*
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* If it's an INSERT ... SELECT there will be a single subquery RTE
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@ -2087,11 +2089,15 @@ get_insert_query_def(Query *query, deparse_context *context)
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context->indentLevel += PRETTYINDENT_STD;
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appendStringInfoChar(buf, ' ');
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}
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appendStringInfo(buf, "INSERT INTO %s",
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appendStringInfo(buf, "INSERT INTO %s (",
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generate_relation_name(rte->relid));
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/* Add the insert-column-names list */
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sep = " (";
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/*
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* Add the insert-column-names list, and make a list of the actual
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* assignment source expressions.
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*/
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strippedexprs = NIL;
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sep = "";
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foreach(l, query->targetList)
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{
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TargetEntry *tle = (TargetEntry *) lfirst(l);
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@ -2101,9 +2107,22 @@ get_insert_query_def(Query *query, deparse_context *context)
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appendStringInfo(buf, sep);
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sep = ", ";
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/*
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* Put out name of target column; look in the catalogs, not at
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* tle->resname, since resname will fail to track RENAME.
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*/
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appendStringInfoString(buf,
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quote_identifier(get_relid_attribute_name(rte->relid,
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tle->resdom->resno)));
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/*
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* Print any indirection needed (subfields or subscripts), and strip
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* off the top-level nodes representing the indirection assignments.
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*/
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strippedexprs = lappend(strippedexprs,
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processIndirection((Node *) tle->expr,
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context));
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}
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appendStringInfo(buf, ") ");
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@ -2113,16 +2132,13 @@ get_insert_query_def(Query *query, deparse_context *context)
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appendContextKeyword(context, "VALUES (",
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-PRETTYINDENT_STD, PRETTYINDENT_STD, 2);
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sep = "";
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foreach(l, query->targetList)
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foreach(l, strippedexprs)
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{
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TargetEntry *tle = (TargetEntry *) lfirst(l);
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if (tle->resdom->resjunk)
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continue; /* ignore junk entries */
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Node *expr = lfirst(l);
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appendStringInfo(buf, sep);
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sep = ", ";
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get_rule_expr((Node *) tle->expr, context, false);
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get_rule_expr(expr, context, false);
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}
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appendStringInfoChar(buf, ')');
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}
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@ -2163,6 +2179,7 @@ get_update_query_def(Query *query, deparse_context *context)
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foreach(l, query->targetList)
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{
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TargetEntry *tle = (TargetEntry *) lfirst(l);
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Node *expr;
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if (tle->resdom->resjunk)
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continue; /* ignore junk entries */
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@ -2171,15 +2188,22 @@ get_update_query_def(Query *query, deparse_context *context)
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sep = ", ";
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/*
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* If the update expression is an array assignment, we mustn't put
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* out "attname =" here; it will come out of the display of the
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* ArrayRef node instead.
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* Put out name of target column; look in the catalogs, not at
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* tle->resname, since resname will fail to track RENAME.
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*/
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if (!tleIsArrayAssign(tle))
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appendStringInfo(buf, "%s = ",
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appendStringInfoString(buf,
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quote_identifier(get_relid_attribute_name(rte->relid,
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tle->resdom->resno)));
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get_rule_expr((Node *) tle->expr, context, false);
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/*
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* Print any indirection needed (subfields or subscripts), and strip
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* off the top-level nodes representing the indirection assignments.
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*/
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expr = processIndirection((Node *) tle->expr, context);
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appendStringInfo(buf, " = ");
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get_rule_expr(expr, context, false);
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}
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/* Add the FROM clause if needed */
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@ -2452,6 +2476,13 @@ isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
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*/
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return (IsA(parentNode, FieldSelect) ? false : true);
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case T_FieldStore:
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/*
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* treat like FieldSelect (probably doesn't matter)
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*/
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return (IsA(parentNode, FieldStore) ? false : true);
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case T_CoerceToDomain:
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/* maybe simple, check args */
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return isSimpleNode((Node *) ((CoerceToDomain *) node)->arg,
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@ -2757,53 +2788,27 @@ get_rule_expr(Node *node, deparse_context *context,
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case T_ArrayRef:
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{
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ArrayRef *aref = (ArrayRef *) node;
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bool savevarprefix = context->varprefix;
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bool need_parens;
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ListCell *lowlist_item;
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ListCell *uplist_item;
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/*
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* If we are doing UPDATE array[n] = expr, we need to
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* suppress any prefix on the array name. Currently, that
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* is the only context in which we will see a non-null
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* refassgnexpr --- but someday a smarter test may be
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* needed.
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* Parenthesize the argument unless it's a simple Var or
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* a FieldSelect. (In particular, if it's another ArrayRef,
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* we *must* parenthesize to avoid confusion.)
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*/
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if (aref->refassgnexpr)
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context->varprefix = false;
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/*
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* Parenthesize the argument unless it's a simple Var.
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*/
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need_parens = (aref->refassgnexpr == NULL) &&
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!IsA(aref->refexpr, Var);
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need_parens = !IsA(aref->refexpr, Var) &&
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!IsA(aref->refexpr, FieldSelect);
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if (need_parens)
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appendStringInfoChar(buf, '(');
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get_rule_expr((Node *) aref->refexpr, context, showimplicit);
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if (need_parens)
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appendStringInfoChar(buf, ')');
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context->varprefix = savevarprefix;
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lowlist_item = list_head(aref->reflowerindexpr);
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foreach(uplist_item, aref->refupperindexpr)
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{
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appendStringInfo(buf, "[");
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if (lowlist_item)
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{
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get_rule_expr((Node *) lfirst(lowlist_item), context,
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false);
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appendStringInfo(buf, ":");
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lowlist_item = lnext(lowlist_item);
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}
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get_rule_expr((Node *) lfirst(uplist_item),
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context, false);
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appendStringInfo(buf, "]");
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}
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printSubscripts(aref, context);
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/*
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* Array assignment nodes should have been handled in
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* processIndirection().
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*/
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if (aref->refassgnexpr)
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{
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appendStringInfo(buf, " = ");
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get_rule_expr((Node *) aref->refassgnexpr, context,
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showimplicit);
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}
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elog(ERROR, "unexpected refassgnexpr");
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}
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break;
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@ -2935,6 +2940,7 @@ get_rule_expr(Node *node, deparse_context *context,
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Oid argType = exprType((Node *) fselect->arg);
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Oid typrelid;
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char *fieldname;
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bool need_parens;
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/* lookup arg type and get the field name */
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typrelid = get_typ_typrelid(argType);
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@ -2943,19 +2949,31 @@ get_rule_expr(Node *node, deparse_context *context,
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format_type_be(argType));
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fieldname = get_relid_attribute_name(typrelid,
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fselect->fieldnum);
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/*
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* If the argument is simple enough, we could emit
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* arg.fieldname, but most cases where FieldSelect is used
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* are *not* simple. So, always use parenthesized syntax.
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* Parenthesize the argument unless it's an ArrayRef or
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* another FieldSelect. Note in particular that it would be
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* WRONG to not parenthesize a Var argument; simplicity is not
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* the issue here, having the right number of names is.
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*/
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appendStringInfoChar(buf, '(');
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get_rule_expr_paren((Node *) fselect->arg, context, true, node);
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appendStringInfoChar(buf, ')');
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need_parens = !IsA(fselect->arg, ArrayRef) &&
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!IsA(fselect->arg, FieldSelect);
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if (need_parens)
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appendStringInfoChar(buf, '(');
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get_rule_expr((Node *) fselect->arg, context, true);
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if (need_parens)
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appendStringInfoChar(buf, ')');
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appendStringInfo(buf, ".%s", quote_identifier(fieldname));
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}
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break;
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case T_FieldStore:
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/*
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* We shouldn't see FieldStore here; it should have been
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* stripped off by processIndirection().
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*/
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elog(ERROR, "unexpected FieldStore");
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break;
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case T_RelabelType:
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{
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RelabelType *relabel = (RelabelType *) node;
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@ -4043,29 +4061,89 @@ get_opclass_name(Oid opclass, Oid actual_datatype,
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}
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/*
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* tleIsArrayAssign - check for array assignment
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* processIndirection - take care of array and subfield assignment
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*
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* We strip any top-level FieldStore or assignment ArrayRef nodes that
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* appear in the input, printing out the appropriate decoration for the
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* base column name (that the caller just printed). We return the
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* subexpression that's to be assigned.
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*/
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static bool
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tleIsArrayAssign(TargetEntry *tle)
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static Node *
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processIndirection(Node *node, deparse_context *context)
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{
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ArrayRef *aref;
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StringInfo buf = context->buf;
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if (tle->expr == NULL || !IsA(tle->expr, ArrayRef))
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return false;
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aref = (ArrayRef *) tle->expr;
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if (aref->refassgnexpr == NULL)
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return false;
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for (;;)
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{
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if (node == NULL)
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break;
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if (IsA(node, FieldStore))
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{
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FieldStore *fstore = (FieldStore *) node;
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Oid typrelid;
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char *fieldname;
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/*
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* Currently, it should only be possible to see non-null refassgnexpr
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* if we are indeed looking at an "UPDATE array[n] = expr" situation.
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* So aref->refexpr ought to match the tle's target.
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*/
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if (aref->refexpr == NULL || !IsA(aref->refexpr, Var) ||
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((Var *) aref->refexpr)->varattno != tle->resdom->resno)
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elog(ERROR, "unrecognized situation in array assignment");
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/* lookup tuple type */
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typrelid = get_typ_typrelid(fstore->resulttype);
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if (!OidIsValid(typrelid))
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elog(ERROR, "argument type %s of FieldStore is not a tuple type",
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format_type_be(fstore->resulttype));
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/*
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* Get the field name. Note we assume here that there's only
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* one field being assigned to. This is okay in stored rules
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* but could be wrong in executable target lists. Presently no
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* problem since explain.c doesn't print plan targetlists, but
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* someday may have to think of something ...
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*/
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fieldname = get_relid_attribute_name(typrelid,
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linitial_int(fstore->fieldnums));
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appendStringInfo(buf, ".%s", quote_identifier(fieldname));
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/*
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* We ignore arg since it should be an uninteresting reference
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* to the target column or subcolumn.
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*/
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node = (Node *) linitial(fstore->newvals);
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}
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else if (IsA(node, ArrayRef))
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{
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ArrayRef *aref = (ArrayRef *) node;
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return true;
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if (aref->refassgnexpr == NULL)
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break;
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printSubscripts(aref, context);
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/*
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* We ignore refexpr since it should be an uninteresting reference
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* to the target column or subcolumn.
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*/
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node = (Node *) aref->refassgnexpr;
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}
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else
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break;
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}
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return node;
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}
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static void
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printSubscripts(ArrayRef *aref, deparse_context *context)
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{
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StringInfo buf = context->buf;
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ListCell *lowlist_item;
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ListCell *uplist_item;
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lowlist_item = list_head(aref->reflowerindexpr); /* could be NULL */
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foreach(uplist_item, aref->refupperindexpr)
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{
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appendStringInfoChar(buf, '[');
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if (lowlist_item)
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{
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get_rule_expr((Node *) lfirst(lowlist_item), context, false);
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appendStringInfoChar(buf, ':');
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lowlist_item = lnext(lowlist_item);
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}
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get_rule_expr((Node *) lfirst(uplist_item), context, false);
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appendStringInfoChar(buf, ']');
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}
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}
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/*
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Reference in New Issue
Block a user