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

TBlobField

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

Base class for BLOB field data

Declaration

Source position: db.pas line 897

type TBlobField = class(TField)

public

  constructor Create(); override;

  

Create a new instance of a TBlobField class.

  procedure Clear; override;

  

Clear the BLOB field's contents

  class function IsBlob; override;

  

Is the field a blob field

  procedure LoadFromFile();

  

Load the contents of the field from a file

  procedure LoadFromStream();

  

Load the field's contents from stream

  procedure SaveToFile();

  

Save field contents to a file

  procedure SaveToStream();

  

Save the field's contents to stream

  procedure SetFieldType(); override;

  

Set field type

  property BlobSize: LongInt; [r]

  

Size of the current blob

  property Modified: Boolean; [rw]

  

Has the field's contents been modified.

  property Value: string; [rw]

  

Return the field's contents as a string

  property Transliterate: Boolean; [rw]

  

Should the contents of the field be transliterated

published

  property BlobType: TBlobType; [rw]

  

Type of blob

  property Size: Integer;

  

Size of the blob field

end;

Inheritance

TBlobField

  

Base class for BLOB field data

|

TField

  

Provide access to the contents of a single field in a record

|

TComponent,IUnknown,IInterfaceComponentReference

|

TPersistent,IFPObserved

|

TObject

Description

TBLobField is the class used when a dataset must manage BLOB data. (TField.DataType equals ftBLOB). It initializes some of the properties of the TField class, and overrides some of its methods to be able to work with BLOB fields. It also serves as parent class for some specialized blob-like field types such as TMemoField, TWideMemoField or TGraphicField

It should never be necessary to create an instance of TBlobField manually, a field of this class will be instantiated automatically for each BLOB field when a dataset is opened.

See also

TDataset

  

Base class for records-based data-access

TField

  

Provide access to the contents of a single field in a record

TMemoField

  

Base class for MEMO (text BLOB) field data

TWideMemoField

  

Field class for wide MEMO (widestring text BLOB) field data

TGraphicField

  

Field class for graphical BLOB field data


Documentation generated on: Jun 22 2020