TBufIndex

type TBufIndex = class(TObject)

public

  DBCompareStruct: TDBCompareStruct;

Structure used when comparing record/field values in the index.

  Name: string;

Name of the index.

  FieldsName: string;

Field names included in the index.

  CaseinsFields: string;

Case-insensitive field names in the index.

  DescFields: string;

Descending fields in the index.

  Options: TIndexOptions;

Options for the index.

  IndNr: Integer;

Ordinal position for the index in the list of indexes.

  constructor Create(); virtual;

Constructor for the class instance.

  function ScrollBackward; virtual; abstract;

Moves to the prior record in the index.

  function ScrollForward; virtual; abstract;

Moves to the next record in the index.

  function GetCurrent; virtual; abstract;

Gets the record buffer for the current record in the dataset.

  function ScrollFirst; virtual; abstract;

Moves to the first record in the index.

  procedure ScrollLast; virtual; abstract;

Moves to the last record in the index.

  function GetRecord(); virtual;

Gets prior/next record relative to the specified bookmark.

  procedure SetToFirstRecord; virtual; abstract;

Sets the index to the first record in the index order.

  procedure SetToLastRecord; virtual; abstract;

Sets the index to the last record in the index order.

  procedure StoreCurrentRecord; virtual; abstract;

Stores the record buffer for the current record.

  procedure RestoreCurrentRecord; virtual; abstract;

Restores the stored record buiffer to the current record.

  function CanScrollForward; virtual; abstract;

Indicates if the index can be scrolled forward.

  procedure DoScrollForward; virtual; abstract;

Implements actions need to scroll forward in the index.

  procedure StoreCurrentRecIntoBookmark(); virtual; abstract;

  procedure StoreSpareRecIntoBookmark(); virtual; abstract;

  procedure GotoBookmark(); virtual; abstract;

Moves the index position to the specified Bookmark.

  function BookmarkValid(); virtual;

Indicates the specified Bookmark is valid.

  function CompareBookmarks(); virtual;

Gets the relative order for the specified Bookmarks.

  function SameBookmarks(); virtual;

Indicates if the specified Bookmarks are for the same record.

  procedure InitialiseIndex; virtual; abstract;

Initializes the index.

  procedure InitialiseSpareRecord(); virtual; abstract;

Initializes values in the spare record for the index.

  procedure ReleaseSpareRecord; virtual; abstract;

Releases resources allocated to the spare record for the index.

  procedure BeginUpdate; virtual; abstract;

  procedure AddRecord; virtual; abstract;

Adds a record to the index.

  procedure InsertRecordBeforeCurrentRecord(); virtual; abstract;

Inserts a record before the current record in the index order.

  procedure RemoveRecordFromIndex(); virtual; abstract;

Remove the record at the specified bookmark from the index.

  procedure OrderCurrentRecord; virtual; abstract;

  procedure EndUpdate; virtual; abstract;

  property SpareRecord: TRecordBuffer; [r]

Spare record for the index.

  property SpareBuffer: TRecordBuffer; [r]

Spare record buffer for the index.

  property CurrentRecord: TRecordBuffer; [r]

Current record in the index.

  property CurrentBuffer: Pointer; [r]

Current record buffer in the index.

  property IsInitialized: Boolean; [r]

Indicates if the index has been initialized.

  property BookmarkSize: Integer; [r]

Size (number of bytes) needed for Bookmarks in the index.

  property RecNo: LongInt; [rw]

Active record number in the index.

end;

TBufIndex

Defines the interface used to implement indexes in TBufDataset.

TObject

TDoubleLinkedBufIndex

Implements an index using a doubly-linked list.

TUniDirectionalBufIndex

Implements a uni-directional index.

TArrayBufIndex

Implements an index using an array of record buffers.