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TLocateOption

TLocateOption = (loCaseInsensitive, loPartialKey)

Example​

procedure FindCustomer(DataSet: TDataSet; var Found: Boolean);
begin
  Found := DataSet.Locate(
    'CustomerCode',
    'ABC',
    [loCaseInsensitive, loPartialKey]);
end;

Usage​

TLocateOption defines case-insensitive and partial-key matching options for a dataset Locate operation.

Members​

ValueOrdinalMeaning
loCaseInsensitive0Compare supported key text without case significance.
loPartialKey1Permit a prefix match on the final supported text key.

Behavior and boundaries​

  • In the Velox client-dataset handling, partial matching appends a wildcard only to the final key field and only when that field is a string, fixed char, wide string, GUID or fixed wide char.
  • Case-insensitive matching is passed into the client-dataset filter expression. Collation and Unicode behavior are Velox-specific, not a culture-independent text contract.
  • Multiple key fields use a Variant array whose order must match the semicolon-separated KeyFields. A scalar is accepted only for one key field.
  • Null key values generate IS NULL; unsupported field kinds raise a bad-field-type database error.
  • The client search starts at BOF and chooses the first filter match. BeforeScroll runs for every attempt; a successful locate moves/resynchronizes the visible cursor and invokes AfterScroll.
  • Locate enters browse mode before searching and can therefore finish pending edit/insert state. Treat it as state-changing, and do not use it concurrently on a shared dataset.
  • TvxClientDataSet.Find always supplies [loCaseInsensitive]; use Locate directly when partial or exact case-sensitive behavior is required.

Additional Technical Info​

TLocateOption is the element type of TLocateOptions, the set passed to a dataset's Locate method. Pass [] for exact, case-sensitive matching or combine the named options in a set.

Velox's modified base TDataSet.Locate returns false; concrete dataset classes implement the search. Because the imported method is virtual, PascalScript dispatches to the actual dataset class. The exact treatment of options is therefore provider-dependent.

External references

Created 2026-07-15