TBufIndex class

In unit BufDataset

Defines the interface used to implement indexes in TBufDataset.

Declaration

pascal

TBufIndex = class(TObject)

Inheritance

TBufIndex
TObject

Descends from it: TArrayBufIndex TDoubleLinkedBufIndex TUniDirectionalBufIndex

Description

TBufIndex is a TObject descendant which defines the interface used to implement indexes in TBufDataset. TBufIndex provides access to the Dataset with field values for the index, and methods to perform record navigation and index maintenance.

TBufIndex contains many virtual and abstract methods that should be implemented in a descendent class which provides a specific index implementation, such as: TDoubleLinkedBufIndex, TUniDirectionalBufIndex, and TArrayBufIndex.

TBufIndex is the type used for the TBufDataset.BufferIndex property.

Properties

`SpareRecord`	public	Spare record for the index.
`SpareBuffer`	public	Spare record buffer for the index.
`CurrentRecord`	public	Current record in the index.
`CurrentBuffer`	public	Current record buffer in the index.
`IsInitialized`	public	Indicates if the index has been initialized.
`BookmarkSize`	public	Size (number of bytes) needed for Bookmarks in the index.
`RecNo`	public	Active record number in the index.

Methods

`GetBookmarkSize`	protected	Gets the value for the BookmarkSize property.
`GetCurrentBuffer`	protected	Gets the value for the CurrentBuffer property.
`GetCurrentRecord`	protected	Gets the value for the CurrentRecord property.
`GetIsInitialized`	protected	Gets the value for the IsInitialized property.
`GetSpareBuffer`	protected	Gets the value for the SpareBuffer property.
`GetSpareRecord`	protected	Gets the value for the SpareRecord property.
`GetRecNo`	protected	Gets the value for the RecNo property.
`SetRecNo`	protected	Sets the value for the RecNo property.
`Create`	public	Constructor for the class instance.
`ScrollBackward`	public	Moves to the prior record in the index.
`ScrollForward`	public	Moves to the next record in the index.
`GetCurrent`	public	Gets the record buffer for the current record in the dataset.
`ScrollFirst`	public	Moves to the first record in the index.
`ScrollLast`	public	Moves to the last record in the index.
`GetRecord`	public	Gets prior/next record relative to the specified bookmark.
`SetToFirstRecord`	public	Sets the index to the first record in the index order.
`SetToLastRecord`	public	Sets the index to the last record in the index order.
`StoreCurrentRecord`	public	Stores the record buffer for the current record.
`RestoreCurrentRecord`	public	Restores the stored record buiffer to the current record.
`CanScrollForward`	public	Indicates if the index can be scrolled forward.
`DoScrollForward`	public	Implements actions need to scroll forward in the index.
`StoreCurrentRecIntoBookmark`	public
`StoreSpareRecIntoBookmark`	public
`GotoBookmark`	public	Moves the index position to the specified Bookmark.
`BookmarkValid`	public	Indicates the specified Bookmark is valid.
`CompareBookmarks`	public	Gets the relative order for the specified Bookmarks.
`SameBookmarks`	public	Indicates if the specified Bookmarks are for the same record.
`InitialiseIndex`	public	Initializes the index.
`InitialiseSpareRecord`	public	Initializes values in the spare record for the index.
`ReleaseSpareRecord`	public	Releases resources allocated to the spare record for the index.
`BeginUpdate`	public
`AddRecord`	public	Adds a record to the index.
`InsertRecordBeforeCurrentRecord`	public	Inserts a record before the current record in the index order.
`RemoveRecordFromIndex`	public	Remove the record at the specified bookmark from the index.
`OrderCurrentRecord`	public
`EndUpdate`	public

Fields

`DBCompareStruct`	public	Structure used when comparing record/field values in the index.
`Name`	public	Name of the index.
`FieldsName`	public	Field names included in the index.
`CaseinsFields`	public	Case-insensitive field names in the index.
`DescFields`	public	Descending fields in the index.
`Options`	public	Options for the index.
`IndNr`	public	Ordinal position for the index in the list of indexes.

Inherited

From TObject (41)

AfterConstruction BeforeDestruction CheckDisposed ClassInfo ClassName ClassNameIs ClassParent ClassType CleanupInstance DefaultHandler DefaultHandlerStr Destroy Dispatch DispatchStr Disposed DisposeOf Equals FieldAddress Free FreeInstance GetDisposed GetHashCode GetInterface GetInterfaceByStr GetInterfaceEntry GetInterfaceEntryByStr GetInterfaceTable GetInterfaceWeak GetLastCastErrorInfo InheritsFrom InitInstance InstanceSize MethodAddress MethodName newinstance QualifiedClassName SafeCallException StringMessageTable SystemHasExtendedRTTI ToString UnitName

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.