Difference between revisions of "locate"
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(Added example, layout, tip to use sql) |
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{{Translate}} | {{Translate}} | ||
| + | ==Definition== | ||
Unit: FreePascal, unit '''db''' | Unit: FreePascal, unit '''db''' | ||
<syntaxhighlight> | <syntaxhighlight> | ||
function Locate(const KeyFields: string; const KeyValues: Variant; Options: TLocateOptions): Boolean; override; | function Locate(const KeyFields: string; const KeyValues: Variant; Options: TLocateOptions): Boolean; override; | ||
| − | |||
</syntaxhighlight> | </syntaxhighlight> | ||
Official documentation: none | Official documentation: none | ||
| + | ==Description== | ||
'''locate''' looks for a record in the dataset where the specified search values for the specified fields match. If found, the function returns true and the cursor position/current record moves to that record. | '''locate''' looks for a record in the dataset where the specified search values for the specified fields match. If found, the function returns true and the cursor position/current record moves to that record. | ||
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{{Note|Locate is only implemented in non-unidirectional datasets, i.e. you must be able to move back and forwards through the dataset.}} | {{Note|Locate is only implemented in non-unidirectional datasets, i.e. you must be able to move back and forwards through the dataset.}} | ||
| + | {{Note|Locate and lookup act at low level inside a dataset to search for records. Often it is more efficient to filter/limit what gets into the dataset in the first place, e.g. using SQL WHERE clauses.}} | ||
| − | == See also == | + | ==Example== |
| + | <syntaxhighlight> | ||
| + | // Using a TDBF dataset | ||
| + | uses dbf, db | ||
| + | ... | ||
| + | // Look for 'di Angelo', 'Di Angelo' etc in a field called | ||
| + | // LASTNAME | ||
| + | if MyDBF.Locate('LASTNAME','di Angelo',[loCaseInsensitive])then | ||
| + | writeln('Found record.'); | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | ==See also== | ||
* [http://delphi.about.com/od/database/l/aa052901a.htm] Description of how to use locate with Delphi | * [http://delphi.about.com/od/database/l/aa052901a.htm] Description of how to use locate with Delphi | ||
[[category:FPC]] | [[category:FPC]] | ||
[[category:Databases]] | [[category:Databases]] | ||
Revision as of 10:22, 15 December 2012
Definition
Unit: FreePascal, unit db
function Locate(const KeyFields: string; const KeyValues: Variant; Options: TLocateOptions): Boolean; override;Official documentation: none
Description
locate looks for a record in the dataset where the specified search values for the specified fields match. If found, the function returns true and the cursor position/current record moves to that record.
KeyFields can be a single field name or a semicolon-separated list of fields.
KeyValue can be a variant or a variant array and the number of items must match the number of fields specified in KeyFields.
Search options can be
- loCaseInsensitive: ignore upper case/lower case differences when searching
- loPartialKey: match partial finds (instead of the complete key)
Note: Locate is only implemented in non-unidirectional datasets, i.e. you must be able to move back and forwards through the dataset. Note: Locate and lookup act at low level inside a dataset to search for records. Often it is more efficient to filter/limit what gets into the dataset in the first place, e.g. using SQL WHERE clauses.Example
// Using a TDBF dataset
uses dbf, db
...
// Look for 'di Angelo', 'Di Angelo' etc in a field called
// LASTNAME
if MyDBF.Locate('LASTNAME','di Angelo',[loCaseInsensitive])then
writeln('Found record.');See also
- [1] Description of how to use locate with Delphi
