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https://github.com/FirebirdSQL/firebird.git
synced 2025-01-23 19:23:03 +01:00
Change ambiguity check for proper handling of sub-queries and non-aliassed (derived)tables.
This doesn't work anymore : "select table.field from table t" But now this does work correctly : "select * from table t join table on (table.ID = t.ID)"
This commit is contained in:
arnobrinkman
parent
5c5127049e
commit
0fb9764dcc
@ -3661,6 +3661,7 @@ static dsql_nod* pass1_field( dsql_req* request, dsql_nod* input, const bool lis
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continue neither the break if node is already allocated. If it isn't evident,
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but this variable is initialized to zero in the declaration above. You
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may write an explicit line to set it to zero here, before the loop.
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3.- Doesn't waste cycles if qualifier is not null. The problem is not the cycles
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themselves, but the fact that you'll detect an ambiguity that doesn't exist: if
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the field appears in more than one context but it's always qualified, then
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@ -3672,6 +3673,13 @@ static dsql_nod* pass1_field( dsql_req* request, dsql_nod* input, const bool lis
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the only allowed qualifier if the alias exists. Hopefully, we will eliminate
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some day this construction: "select table.field from table t" because it
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should be "t.field" instead.
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AB: 2004-01-09
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The explained query directly above doesn't work anymore, thus the day has come ;-)
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It's allowed to use the same fieldname between different scope levels (sub-queries)
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without being hit by the ambiguity check. The field uses the first match starting
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from it's own level (ofcourse ambiguity-check on each level is done).
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4.- Doesn't verify code derived automatically from check constraints. They are
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ill-formed by nature but making that code generation more orthodox is not a
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priority. Typically, they only check a field against a contant. The problem
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@ -3686,165 +3694,184 @@ static dsql_nod* pass1_field( dsql_req* request, dsql_nod* input, const bool lis
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dsql_lls* ambiguous_ctx_stack = NULL;
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dsql_nod* node = 0; // This var must be initialized.
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for (dsql_lls* stack = request->req_context; stack; stack = stack->lls_next)
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{
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// resolve_context() checks the type of the
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// given context, so the cast to dsql_ctx* is safe.
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dsql_ctx* context = reinterpret_cast<dsql_ctx*>(stack->lls_object);
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// AB: Loop through the scope_levels starting by its own.
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USHORT current_scope_level = request->req_scope_level + 1;
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for (; current_scope_level > 0; current_scope_level--) {
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dsql_fld* field;
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if (request->req_alias_relation_prefix && qualifier) {
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dsql_str* req_qualifier = pass1_alias_concat(request->req_alias_relation_prefix, qualifier);
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field = resolve_context(request, req_qualifier, context);
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delete req_qualifier;
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// If we've found a node we're done.
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if (node) {
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break;
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}
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else {
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field = resolve_context(request, qualifier, context);
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}
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// AB: When there's no relation and no procedure then we have a derived table.
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bool is_derived_table = (!context->ctx_procedure && !context->ctx_relation && context->ctx_rse);
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if (field)
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for (dsql_lls* stack = request->req_context; stack; stack = stack->lls_next)
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{
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// If there's no name then we have most probable an asterisk that
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// needs to be exploded. This should be handled by the caller and
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// when the caller can handle this, list is true.
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if (!name) {
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if (list) {
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node = MAKE_node(nod_relation, e_rel_count);
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node->nod_arg[e_rel_context] = reinterpret_cast<dsql_nod*>(stack->lls_object);
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return node;
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}
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else {
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break;
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}
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// resolve_context() checks the type of the
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// given context, so the cast to dsql_ctx* is safe.
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dsql_ctx* context = reinterpret_cast<dsql_ctx*>(stack->lls_object);
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if (context->ctx_scope_level != (current_scope_level - 1)) {
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continue;
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}
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for (; field; field = field->fld_next) {
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if (!strcmp(reinterpret_cast<const char*>(name->str_data), field->fld_name)) {
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if (!is_check_constraint && !qualifier) {
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LLS_PUSH(context, &ambiguous_ctx_stack);
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}
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break;
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}
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dsql_fld* field;
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if (request->req_alias_relation_prefix && qualifier) {
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dsql_str* req_qualifier =
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pass1_alias_concat(request->req_alias_relation_prefix, qualifier);
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field = resolve_context(request, req_qualifier, context);
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delete req_qualifier;
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}
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if (qualifier && !field) {
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break;
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else {
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field = resolve_context(request, qualifier, context);
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}
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// AB: When there's no relation and no procedure then we have a derived table.
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bool is_derived_table =
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(!context->ctx_procedure && !context->ctx_relation && context->ctx_rse);
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if (field) {
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// Intercept any reference to a field with datatype that
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// did not exist prior to V6 and post an error
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if (request->req_client_dialect <= SQL_DIALECT_V5 &&
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(field->fld_dtype == dtype_sql_date ||
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field->fld_dtype == dtype_sql_time ||
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field->fld_dtype == dtype_int64))
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{
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ERRD_post(isc_sqlerr, isc_arg_number, (SLONG) - 206,
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isc_arg_gds, isc_dsql_field_err,
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isc_arg_gds, isc_random,
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isc_arg_string, field->fld_name,
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isc_arg_gds,
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isc_sql_dialect_datatype_unsupport,
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isc_arg_number, request->req_client_dialect,
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isc_arg_string,
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DSC_dtype_tostring(static_cast < UCHAR >
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(field->fld_dtype)), 0);
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return NULL;
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};
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// CVC: Stop here if this is our second or third iteration.
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// Anyway, we can't report more than one ambiguity to the status vector.
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if (node) {
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continue;
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}
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if (indices) {
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indices = PASS1_node(request, indices, false);
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}
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node = MAKE_field(context, field, indices);
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if (is_check_constraint || qualifier) {
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break;
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}
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}
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}
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else if (is_derived_table) {
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// if an qualifier is present check if we have the same derived
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// table else continue;
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if (qualifier) {
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if (context->ctx_alias) {
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if (strcmp(reinterpret_cast<const char*>(qualifier->str_data),
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reinterpret_cast<const char*>(context->ctx_alias))) {
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continue;
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}
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}
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else {
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continue;
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}
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}
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// If there's no name then we have most probable a asterisk that
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// needs to be exploded. This should be handled by the caller and
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// when the caller can handle this, list is true.
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if (!name) {
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if (list) {
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// Node is created so caller pass1_sel_list() can deal with it.
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node = MAKE_node(nod_derived_table, e_derived_table_count);
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node->nod_arg[e_derived_table_rse] = context->ctx_rse;
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return node;
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}
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else {
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break;
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}
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}
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// Because every select item has an alias we can just walk
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// through the list and return the correct node when found.
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const dsql_nod* rse_items = context->ctx_rse->nod_arg[e_rse_items];
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dsql_nod* const* ptr = rse_items->nod_arg;
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for (const dsql_nod* const* const end = ptr + rse_items->nod_count;
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ptr < end; ptr++)
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if (field)
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{
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dsql_nod* node_select_item = *ptr;
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// select-item should always be a alias!
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if (node_select_item->nod_type == nod_derived_field) {
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const dsql_str* string = (dsql_str*) node_select_item->nod_arg[e_derived_field_name];
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if (!strcmp(reinterpret_cast<const char*>(name->str_data),
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reinterpret_cast<const char*>(string->str_data)))
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{
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// This is a matching item so add the context to the ambiguous list.
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if (!is_check_constraint && !qualifier) {
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LLS_PUSH(context, &ambiguous_ctx_stack);
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}
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// Stop here if this is our second or more iteration.
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if (node) {
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break;
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}
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node = node_select_item;
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// If there's no name then we have most probable an asterisk that
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// needs to be exploded. This should be handled by the caller and
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// when the caller can handle this, list is true.
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if (!name) {
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if (list) {
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node = MAKE_node(nod_relation, e_rel_count);
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node->nod_arg[e_rel_context] = reinterpret_cast<dsql_nod*>(stack->lls_object);
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return node;
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}
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else {
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break;
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}
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}
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else {
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// Internal dsql error: alias type expected by field.
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//
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// !!! THIS MESSAGE SHOULD BE CHANGED !!!
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//
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ERRD_post(isc_sqlerr, isc_arg_number, (SLONG) - 104,
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isc_arg_gds, isc_dsql_command_err, 0);
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}
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}
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// If we found the field and qualifier is present or this
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// is a check constraint we're done.
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if (node && (is_check_constraint || qualifier)) {
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break;
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for (; field; field = field->fld_next) {
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if (!strcmp(reinterpret_cast<const char*>(name->str_data), field->fld_name)) {
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if (!is_check_constraint && !qualifier) {
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LLS_PUSH(context, &ambiguous_ctx_stack);
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}
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break;
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}
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}
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if (qualifier && !field) {
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break;
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}
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if (field) {
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// Intercept any reference to a field with datatype that
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// did not exist prior to V6 and post an error
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if (request->req_client_dialect <= SQL_DIALECT_V5 &&
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(field->fld_dtype == dtype_sql_date ||
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field->fld_dtype == dtype_sql_time ||
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field->fld_dtype == dtype_int64))
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{
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ERRD_post(isc_sqlerr, isc_arg_number, (SLONG) - 206,
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isc_arg_gds, isc_dsql_field_err,
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isc_arg_gds, isc_random,
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isc_arg_string, field->fld_name,
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isc_arg_gds,
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isc_sql_dialect_datatype_unsupport,
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isc_arg_number, request->req_client_dialect,
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isc_arg_string,
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DSC_dtype_tostring(static_cast < UCHAR >
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(field->fld_dtype)), 0);
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return NULL;
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};
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// CVC: Stop here if this is our second or third iteration.
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// Anyway, we can't report more than one ambiguity to the status vector.
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// AB: But only if we're on different scope level, because a
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// node inside the same context should have priority.
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if (node) {
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continue;
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}
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if (indices) {
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indices = PASS1_node(request, indices, false);
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}
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node = MAKE_field(context, field, indices);
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if (is_check_constraint || qualifier) {
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break;
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}
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}
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}
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else if (is_derived_table) {
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// if an qualifier is present check if we have the same derived
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// table else continue;
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if (qualifier) {
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if (context->ctx_alias) {
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if (strcmp(reinterpret_cast<const char*>(qualifier->str_data),
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reinterpret_cast<const char*>(context->ctx_alias))) {
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continue;
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}
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}
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else {
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continue;
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}
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}
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// If there's no name then we have most probable a asterisk that
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// needs to be exploded. This should be handled by the caller and
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// when the caller can handle this, list is true.
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if (!name) {
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if (list) {
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// Node is created so caller pass1_sel_list() can deal with it.
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node = MAKE_node(nod_derived_table, e_derived_table_count);
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node->nod_arg[e_derived_table_rse] = context->ctx_rse;
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return node;
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}
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else {
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break;
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}
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}
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// Because every select item has an alias we can just walk
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// through the list and return the correct node when found.
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const dsql_nod* rse_items = context->ctx_rse->nod_arg[e_rse_items];
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dsql_nod* const* ptr = rse_items->nod_arg;
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for (const dsql_nod* const* const end = ptr + rse_items->nod_count;
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ptr < end; ptr++)
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{
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dsql_nod* node_select_item = *ptr;
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// select-item should always be a alias!
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if (node_select_item->nod_type == nod_derived_field) {
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const dsql_str* string =
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(dsql_str*) node_select_item->nod_arg[e_derived_field_name];
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if (!strcmp(reinterpret_cast<const char*>(name->str_data),
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reinterpret_cast<const char*>(string->str_data)))
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{
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// This is a matching item so add the context to the ambiguous list.
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if (!is_check_constraint && !qualifier) {
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LLS_PUSH(context, &ambiguous_ctx_stack);
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}
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// Stop here if this is our second or more iteration.
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if (node) {
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break;
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}
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node = node_select_item;
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break;
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}
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}
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else {
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// Internal dsql error: alias type expected by field.
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//
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// !!! THIS MESSAGE SHOULD BE CHANGED !!!
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//
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ERRD_post(isc_sqlerr, isc_arg_number, (SLONG) - 104,
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isc_arg_gds, isc_dsql_command_err, 0);
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}
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}
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// If we found the field and qualifier is present or this
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// is a check constraint we're done.
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if (node && (is_check_constraint || qualifier)) {
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break;
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}
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}
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}
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}
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@ -6732,31 +6759,29 @@ static dsql_fld* resolve_context( dsql_req* request, const dsql_str* qualifier,
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return NULL;
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}
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/* if there is no qualifier, then we cannot match against
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a context of a different scoping level */
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if (!qualifier && context->ctx_scope_level != request->req_scope_level) {
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return NULL;
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}
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// if there is no qualifier, then we cannot match against
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// a context of a different scoping level
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// AB: Yes we can, but the scope level where the field is has priority.
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// if (!qualifier && context->ctx_scope_level != request->req_scope_level) {
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// return NULL;
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// }
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TEXT* table_name;
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if (relation) {
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table_name = relation->rel_name;
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if (context->ctx_alias) {
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table_name = context->ctx_alias;
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}
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else {
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table_name = procedure->prc_name;
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if (relation) {
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table_name = relation->rel_name;
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}
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else {
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table_name = procedure->prc_name;
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}
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}
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fb_utils::fb_exact_name(table_name);
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/* If a context qualifier is present, make sure this is the
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proper context */
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if (qualifier &&
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strcmp(reinterpret_cast<const char*>(qualifier->str_data), table_name)
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&& (!context->ctx_alias
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|| strcmp(reinterpret_cast<const char*>(qualifier->str_data),
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context->ctx_alias)))
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{
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// If a context qualifier is present, make sure this is the proper context
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if (qualifier && strcmp(reinterpret_cast<const char*>(qualifier->str_data), table_name)) {
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return NULL;
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}
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Block a user