CheckAll
function CheckAll: string;
Example
function CurrentChangeInput(const View: TdaCDSQueryDataView): string;
begin
Result := View.CheckAll;
end;
Usage
CheckAll concatenates every pipeline field's AsString value in field order as a fast change hint, without names, lengths, separators or null markers.
- Use only as a fast, process-local change input where collision risk is acceptable.
- For durable identity or audit, serialize field names, types, null markers and lengths canonically before hashing.
- Ensure the view has a pipeline and active fields; missing pipeline/index/conversion errors propagate.
Additional Technical Info
CheckAll builds the string used as input by some Hash.HasChanged workflows. It is not itself a cryptographic hash or an unambiguous record serialization.
Source-backed behaviour
The base implementation lazily creates one TvxStringAppend with initial capacity 400, resets its position, reads DataPipelines[0].FieldCount, and appends FieldByIndex(i).AsString for every field in collection order. It returns the builder's current data. Concrete descendants inherit this implementation while overriding FieldByIndex to read their client dataset.
There is no field name, delimiter, length, type or null marker. Values ('AB','C') and ('A','BC') therefore produce the same text; null and empty string commonly both contribute nothing. Numeric/date string conversion can be locale- or descendant-dependent. Field reordering changes the result. The cached builder is mutable view state and is not synchronized for concurrent calls.