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FireDAC.Stan.Option.TFDFetchOptions.Unidirectional

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Delphi

property Unidirectional: Boolean read GetUnidirectional  write SetUnidirectional stored IsUS default False;

C++

__property bool Unidirectional = {read=GetUnidirectional, write=SetUnidirectional, stored=IsUS, default=0};

Properties

Type Visibility Source Unit Parent
property published
FireDAC.Stan.Option.pas
FireDAC.Stan.Option.hpp
FireDAC.Stan.Option TFDFetchOptions

Description

Specifies possible directions of navigation by dataset records.

Use the Unidirectional property to specify whether an application will navigate by dataset records in forward-only direction or in forward, backward and random directions. To change Unidirectional for an already used dataset, an application can call the Disconnect method first. 

Setting Unidirectional to True enables an application to navigate in forward-only direction. FireDAC will automatically discard prior rows from the internal data storage after moving the current position in the dataset, because they are not needed anymore. This dramatically reduces memory consumption on big result sets.  Setting Unidirectional to True for TFDTable disables the live data window mode.

Note: Do not use Unidirectional datasets to display data in grid control. It requires bi-directional datasets.

The Unidirectional property is synchronized with IsUniDirectional.

See Also

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