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

TFpcBinaryDatapacketReader

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

Implements a data packet reader using binary data packets

Declaration

Source position: bufdataset.pas line 415

type TFpcBinaryDatapacketReader = class(TDataPacketReader)

public

  constructor Create(); override;

  

Constructor for the class instance

  procedure LoadFieldDefs(); override;

  

Loads field definitions using the data packet reader

  procedure StoreFieldDefs(); override;

  

Stores field definitions using the data packet reader

  procedure InitLoadRecords; override;

  

  function GetCurrentRecord; override;

  

  function GetRecordRowState(); override;

  

  procedure RestoreRecord; override;

  

  procedure GotoNextRecord; override;

  

  procedure StoreRecord(); override;

  

  procedure FinalizeStoreRecords; override;

  

  class function RecognizeStream(); override;

  

end;

Inheritance

TFpcBinaryDatapacketReader

  

Implements a data packet reader using binary data packets

|

TDataPacketReader

  

Implements a data packet reader for TBufDataset

|

TObject

Description

TFpcBinaryDatapacketReader is a TDatapacketReader descendant that implements a data packet reader using binary data packets. Binary data packets use the following layout:

Section Name Length Description
Header Identification 13 bytes Contains the value 'BinBufDataSet'
Version 1 byte Version number
Field Definition Count 2 bytes Column Layout for field definition values
Field Definitions Field Name Length 2 bytes Section occurs the number of times indicated in Field Definition Count
Field Name See above Name of the field in the dataset
Display Name Length 2 bytes
Display Name See above Caption for the field
Data Type 2 bytes
Read-Only Attribute 1 byte 0=read/write, 1=read-only
Parameters AutoInc Value 4 bytes Integer value for the auto-increment field type
Row Header Row Marker 1 byte Contains the value $fe
Row State 1 byte 0=original, 1=deleted, 2=inserted, 3=modified
Update Order 4 bytes
Null Bitmap Variable length. 1 byte required for eight fields; 2 bytes for 16 fields, etc. See Field Definition Count. Bit values are set to 1 when the corresponding field is null.
Row Data Optional Field Length 4 bytes Variable-length fields are prefixed with their length. Fixed-length fields do not require this entry. Null fields are not stored.
Field Data Bytes values for the field. See Optional Field Length. Occurs the number of times needed for Field Definition Count.

See also

TDatapacketReader

  

Implements a data packet reader for TBufDataset


Documentation generated on: Jun 22 2020