FireDAC.Comp.DataSet.TFDDataSet.Locate
Delphi
function Locate(const AKeyFields: string; const AKeyValues: Variant;
AOptions: TLocateOptions = []): Boolean; override;
C++
virtual bool __fastcall Locate(const System::UnicodeString AKeyFields, const System::Variant &AKeyValues, Data::Db::TLocateOptions AOptions = Data::Db::TLocateOptions() );
Contents
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
| function | public | FireDAC.Comp.DataSet.pas FireDAC.Comp.DataSet.hpp |
FireDAC.Comp.DataSet | TFDDataSet |
Description
Searches the dataset for a record with the specified field values and makes it current.
Use Locate to search the dataset for a record with the specified field values and make it current if found.
AKeyFields is a semicolon-separated list of field names through which to search.
AKeyValues is a Variant that contains the values to match the key fields. If AKeyFields contains a single field name, then AKeyValues is a simple value. If AKeyFields contains more field names, then AKeyValues is a variant array where items correspond to the key fields.
AOptions is a set of search modes for string fields. If AOptions contains loCaseInsensitive, then Locate ignores case when matching fields. If AOptions contains loPartialKey, then the AKeyValues parameter can contain partial strings.
If a matching record is found, then this record becomes current and Locate returns True.
To optimize record searching, the application can set up a client index. The index will be used by Locate if the following conditions are met:
- The index field list has as prefix
AKeyFieldsfields. - The index is built with the
soNoCaseoption andAOptionsincludesloCaseInsensitive, or the index is build withoutsoNoCaseandAOptionsdoes not includeloCaseInsensitive. - The index is active and is current.
Example
CustTable.IndexFieldNames := 'ID';
if CustTable.Locate('ID', 1001, []) then
CustTable.Delete
else
ShowMessage('The customer with ID=1001 is not found');