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loCaseInsensitive

loCaseInsensitive = 0

Example​

procedure FindCustomer(DataSet: TDataSet; var Found: Boolean);
begin
  Found := DataSet.Locate(
    'CustomerCode',
    'abc-100',
    [loCaseInsensitive]);
end;

Usage​

loCaseInsensitive requests case-insensitive text matching when a dataset Locate supports that option.

Additional Technical Info​

loCaseInsensitive is a TLocateOption member that requests a case-insensitive comparison for supported text keys in a dataset Locate operation. It belongs inside a TLocateOptions set; its ordinal zero is an implementation detail, not the options value to pass directly.

The example searches CustomerCode without treating letter case as significant. The actual result depends on the active dataset, stored values and its text comparison rules. It is source-reviewed and is not executed by the documentation workflow.

Velox registration and dispatch

The dataset import defines TLocateOption = (loCaseInsensitive, loPartialKey), defines TLocateOptions as its set, and exposes the virtual TDataSet.Locate method. The option is handled by the concrete dataset instance at runtime.

Velox's modified base TDataSet.Locate simply returns False. A class that does not override it will therefore appear to find no match rather than raising a not-implemented error. TvxClientDataSet inherits the substantive TCustomClientDataSet implementation, and its convenience Find method always supplies [loCaseInsensitive].

Current client-dataset behavior

For the client-dataset path used by TvxClientDataSet, the option adds foCaseInsensitive to the filter expression used for the search. It affects supported textual comparisons; it does not convert nontext values or define a universal Unicode/culture collation.

The locate process:

  1. enters/checks browse mode and updates cursor state;
  2. resolves the semicolon-separated key fields and aligned key values;
  3. moves its search cursor to BOF;
  4. finds the first matching record through the expression engine; and
  5. on success, resynchronizes the visible dataset cursor and fires AfterScroll.

BeforeScroll runs before the attempt, including an ordinary no-match. A locate is therefore stateful even though its return type is Boolean.

Case, collation and data boundaries

  • Case folding is defined by the concrete dataset/expression engine. Do not assume invariant, locale-neutral, database-server or Unicode normalization semantics.
  • Case-insensitive is not accent-insensitive. Do not infer that punctuation, whitespace, composed/decomposed Unicode or locale-specific letters compare equivalently.
  • The option does not trim values. Normalize data explicitly when the business key contract requires trimming or Unicode normalization.
  • With multiple key fields the option applies to supported text comparisons in the constructed expression; numeric/date/Boolean keys keep their type-specific comparison.
  • Combine it with loPartialKey only when a case-insensitive prefix search is intended.

Dataset state, events and concurrency

CheckBrowseMode can finish pending edit/insert state according to the dataset contract. BeforeScroll code can raise or change application state, and a successful locate changes the current record and calls AfterScroll. Do not call Locate as though it were a pure predicate and do not concurrently navigate a shared dataset instance.

Errors

The option itself does not raise. Locate can fail or raise for inactive datasets, invalid/missing fields, misaligned Variant arrays, unsupported key field types, failed conversions, provider/filter errors or event-handler exceptions.

Performance

The current client-dataset path starts at BOF and evaluates a filter to find the first match. Repeated case-insensitive locates over a large in-memory dataset can be expensive; do not assume a database index or server-side query is used.

Related entries

External references

Created 2026-07-15