[Overview][Types][Classes][Procedures and functions][Index] Reference for unit 'BufDataset' (#fcl)

TBufDataset

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

Implements a database-aware buffered dataset

Declaration

Source position: bufdataset.pas line 670

type TBufDataset = class(TCustomBufDataset)

published

  property MaxIndexesCount: Integer;

  property FieldDefs: TFieldDefs;

  

Definitions of available fields in the underlying database

  property Active: Boolean;

  

Is the dataset open or closed.

  property AutoCalcFields: Boolean;

  

How often should the value of calculated fields be calculated

  property Filter: string;

  

Filter to apply to the data in memory.

  property Filtered: Boolean;

  

Is the filter active or not.

  property ReadOnly: Boolean;

  property AfterCancel: TDataSetNotifyEvent;

  

Event triggered after a Cancel operation.

  property AfterClose: TDataSetNotifyEvent;

  

Event triggered after the dataset is closed

  property AfterDelete: TDataSetNotifyEvent;

  

Event triggered after a successful Delete operation.

  property AfterEdit: TDataSetNotifyEvent;

  

Event triggered after the dataset is put in edit mode.

  property AfterInsert: TDataSetNotifyEvent;

  

Event triggered after the dataset is put in insert mode.

  property AfterOpen: TDataSetNotifyEvent;

  

Event triggered after the dataset is opened.

  property AfterPost: TDataSetNotifyEvent;

  

Event called after changes have been posted to the underlying database

  property AfterScroll: TDataSetNotifyEvent;

  

Event triggered after the cursor has changed position.

  property BeforeCancel: TDataSetNotifyEvent;

  

Event triggered before a Cancel operation.

  property BeforeClose: TDataSetNotifyEvent;

  

Event triggered before the dataset is closed.

  property BeforeDelete: TDataSetNotifyEvent;

  

Event triggered before a Delete operation.

  property BeforeEdit: TDataSetNotifyEvent;

  

Event triggered before the dataset is put in edit mode.

  property BeforeInsert: TDataSetNotifyEvent;

  

Event triggered before the dataset is put in insert mode.

  property BeforeOpen: TDataSetNotifyEvent;

  

Event triggered before the dataset is opened.

  property BeforePost: TDataSetNotifyEvent;

  

Event called before changes are posted to the underlying database

  property BeforeScroll: TDataSetNotifyEvent;

  

Event triggered before the cursor changes position.

  property OnCalcFields: TDataSetNotifyEvent;

  

Event triggered when values for calculated fields must be computed.

  property OnDeleteError: TDataSetErrorEvent;

  

Event triggered when a delete operation fails.

  property OnEditError: TDataSetErrorEvent;

  

Event triggered when an edit operation fails.

  property OnFilterRecord: TFilterRecordEvent;

  

Event triggered to filter records.

  property OnNewRecord: TDataSetNotifyEvent;

  

Event triggered when a new record is created.

  property OnPostError: TDataSetErrorEvent;

  

Event triggered when a post operation fails.

end;

Inheritance

TBufDataset

  

Implements a database-aware buffered dataset

|

TCustomBufDataset

  

Dataset connected to a database.

|

TDBDataset

  

Dataset connected to a database.

|

TDataSet

  

Base class for records-based data-access

|

TComponent,IUnknown,IInterfaceComponentReference

|

TPersistent,IFPObserved

|

TObject

Description

TBufDataset is a TCustomBufDataset descendant that implements a database-aware buffered dataset. TBufDataset is an in-memory dataset that can be used as a local stand-alone dataset, or it can be used as a local buffer for updates applied to a remote dataset. TBufDataset implements many features similar to those in TClientDataset in Delphi. However, it is not meant to be code or function compatible with TClientDataset. It is designed to provide management of the buffers used to access record data, and is used as the ancestor for classes like TSQLQuery and TRESTBufDataset.

As a TDBDataset descendent, it offers access to many of the database features supported in the FCL DB package. As a TDataset descendent, it also offers access to familiar navigation and data handling methods in the ancestor class. TBufDataset has features that allow local storage and retrieval of field definitions and record data. In addition, facilities are provided that allow local indexing of record data in the dataset. There is a comprehensive parser/expression evaluator available that allows complete support for Filters in the dataset.

TBufDataset sets the visibility for properties and methods defined in the ancestor class.

Additional information about using TBufDataset can be found on the Lazarus Wiki at: How to write in-memory database applications in Lazarus/FPC (TBufDataset).

See also

TCustomBufDataset

  

Dataset connected to a database.

TDataset

  

Base class for records-based data-access

TDBDataset

  

Dataset connected to a database.


Documentation generated on: Jun 22 2020