New Features in Version 4.x

The following items are new features in version 4.x:

There is a new TDBISAMEngine component that encapsulates the DBISAM engine inside of a visual component. In the component hierarchy, the TDBISAMEngine component sits at the top above the TDBISAMSession component(s). A default Engine function is available in the dbisamtb unit (Delphi) or dbisamtb header file (C++) that points to a global instance of the TDBISAMEngine component. You can also drop a TDBISAMEngine component on a form or data-module to visually change its properties. However, only one instance of the TDBISAMEngine component can exist in a given application, and both the Engine function and any TDBISAMEngine component on a form or data module point to the same instance of the component (singleton model). Some of the functionality found in the TDBISAMEngine component includes:

Functionality

Description

Engine Type	The EngineType property can be set to either etClient or etServer in order to have the engine behave as a local client engine or a server engine. If acting as a server engine, many additional properties are provided for configuring the server: ServerName ServerDescription ServerMainAddress ServerMainPort ServerMainThreadCacheSize ServerAdminAddress ServerAdminPort ServerAdminThreadCacheSize ServerEncryptedOnly ServerEncryptionPassword ServerConfigFileName ServerConfigPassword There are also many events provided for the server engine: OnServerStart OnServerStop OnServerLogEvent OnServerLogCount OnServerLogRecord OnServerConnect OnServerReconnect OnServerLogin OnServerLogout OnServerDisconnect OnServerScheduledEvent OnServerProcedure Please see the Configuring and Starting the Server topic for more information.
Full Text Indexing	There are specific events for implementing full text index filtering (either on a buffer basis or on a per-token basis): OnTextIndexFilter OnTextIndexTokenFilter Also, there are two new methods for parsing strings into word lists and retrieving the default text indexing parameters: BuildWordList GetDefaultTextIndexParams The BuildWordList function used to be available in the dbisamlb unit (Delphi) or dbisamlb header file (C++) and it is still is, although different from the one available as a method of the TDBISAMEngine component. You should use the method of the TDBISAMEngine component instead of the function in the dbisamlb unit in version 4. Please see the Full Text Indexing topic for more information.
Custom Encryption	There are specific events for customizing the encryption in DBISAM (8-byte block ciphers only): OnCryptoInit OnEncryptBlock OnDecryptBlock OnCryptoReset Please see the Encryption topic for more information.
Custom Compression	There are specific events for customizing the compression in DBISAM: OnCompress OnDecompress Please see the Compression topic for more information.
Signatures	There is an EngineSignature property in the TDBISAMEngine component that is used to create an MD5 hash that is assigned to every table, table stream, backup, comms request and response, etc. This allows one to "assign" tables, etc. to a specific application and prevent any other application from accessing the tables, server, etc. without the proper engine signature. Please see the Customizing the Engine for more information.
ANSI Conversions	All of the ANSI string conversion functions that used to be in the dbisamlb unit are now public methods of the TDBISAMEngine component: DateToAnsiStr TimeToAnsiStr DateTimeToAnsiStr AnsiStrToDate AnsiStrToTime AnsiStrToDateTime BooleanToAnsiStr AnsiStrToBoolean FloatToAnsiStr AnsiStrToFloat CurrToAnsiStr AnsiStrToCurr
Locale Functionality	There are new methods for working with the available locales in DBISAM: IsValidLocale IsValidLocaleConstant ConvertLocaleConstantToID ConvertIDToLocaleConstant GetLocaleNames
Memory Usage	The amount of memory used for buffering tables can now be controlled via the following properties: MaxTableDataBufferSize MaxTableDataBufferCount MaxTableIndexBufferSize MaxTableIndexBufferCount MaxTableBlobBufferSize MaxTableBlobBufferCount These properties used to be in the TDBISAMSession component in 3.x and earlier and were only applicable to the session for which they were configured. The TDBISAMEngine properties above are used for the all sessions in the application.
File Extensions	The file extensions to use for physical table files, table backup files, and table upgrade backup files can be specified via the following properties: TableDataExtension TableIndexExtension TableBlobExtension TableDataBackupExtension TableIndexBackupExtension TableBlobBackupExtension TableDataUpgradeExtension TableIndexUpgradeExtension TableBlobUpgradeExtension
Locking	The lock wait times and retry counts for table read, write, and transaction locks can now be modified via the following properties: TableReadLockTimeout TableWriteLockTimeout TableTransLockTimeout
Triggers	You can now define trigger event handlers that allow for processing both before and after the execution of an insert, update, or delete operation: BeforeInsertTrigger AfterInsertTrigger BeforeUpdateTrigger AfterUpdateTrigger BeforeDeleteTrigger AfterDeleteTrigger Please see the Customizing the Engine topic for more information.
Custom Functions	You can now add custom functions for use with filters and SQL statements. They can be used anywhere that a normal, non-aggregate function would be used. All arguments to the functions are required and there is no facility currently for optional arguments. The Functions property of the TDBISAMEngine component allows you to specify the functions and their arguments, and the OnCustomFunction event of the TDBISAMEngine component allows you to implement the functions. Please see the Customizing the Engine topic for more information.

You can now use restricted transactions on a given database where only certain tables that you specify are involved in the transaction. Please see the Transactions topic for more information.

There is a new TDBISAMEngine FilterRecordCounts property that controls how record counts are returned for filtered datasets and live query result sets. The default value of this property is True, which indicates that record counts under these circumstances will be returned in the same fashion as they were in 3.x and earlier. If the FilterRecordCounts property is set to False, the RecordCount property of the TDBISAMTable and TDBISAMQuery components will always show the total record count of the entire dataset or active range (if a range is set) only and will not take any active filters (or WHERE clauses with live query result sets) into account. To get the record count including any active filters, a FilterRecordCount property has been added to the TDBISAMTable and TDBISAMQuery components that always shows the accurate record count, regardless of the current setting of the TDBISAMEngine FilterRecordCounts propety.

Setting the TDBISAMEngine FilterRecordCounts property to False may be desirable for some applications since it allows for more accurate positioning of the scroll bar in a TDBGrid or similar multi-row, data-aware components. Please see the Customizing the Engine and Setting Filters on Tables topics for more information.

The TDBISAMSession component now has new remote administrative methods for adding/updating/deleting server-side procedures and events:

   GetRemoteProcedureNames
   GetRemoteProcedure
   AddRemoteProcedure
   ModifyRemoteProcedure
   DeleteRemoteProcedure
   GetRemoteProcedureUserNames
   GetRemoteProcedureUser
   AddRemoteProcedureUser
   ModifyRemoteProcedureUser
   DeleteRemoteProcedureUser
   GetRemoteEventNames
   GetRemoteEvent
   AddRemoteEvent
   ModifyRemoteEvent
   DeleteRemoteEvent

Please see the Server Administration topic for more information.

The TDBISAMSession component now has the ability to ping a database server using the RemotePing and RemotePingInterval properties. These properties eliminate the need for user-constructed pinging operations using timers and are safe to use for the purpose of shortening dead session expiration times that are configured on a database server and eliminating dangling pessimistic locks when client workstations go down while connected.

The TDBISAMSession component now has the capability to call a server-side procedure on a database server using the CallRemoteProcedure method, the RemoteParams property, and the RemoteParamByName method. Please see the Calling Server-Side Procedures topic for more information.

The TDBISAMDatabase component has new backup and restore facilities available in the following methods and events:

   Backup
   BackupInfo
   Restore

   OnBackupProgress
   OnBackupLog
   OnRestoreProgress
   OnRestoreLog

Please see the Backing Up and Restoring Databases topic for more information.

There is a new TableSize property for the TDBISAMTable component that reflects the total size (in bytes) of the physical table on disk (or in-memory if an in-memory table).

The SQL SELECT statement now includes support for the EXCEPT [ALL] and INTERSECT [ALL] set operations, in addition to the UNION [ALL] operation.

There are several new SQL statements available:

   EMPTY TABLE
   OPTIMIZE TABLE
   EXPORT TABLE
   IMPORT TABLE
   VERIFY TABLE
   REPAIR TABLE
   UPGRADE TABLE
   RENAME TABLE

There are several new filter and SQL functions:

   STDDEV (aggregate, SQL-only)
   CURRENT_GUID
   YEARSFROMMSECS
   DAYSFROMMSECS
   HOURSFROMMSECS
   MINSFROMMSECS
   SECSFROMMSECS
   MSECSFROMMSECS
   LTRIM
   RTRIM
   REPEAT
   CONCAT
   MOD
   ACOS
   ASIN
   ATAN
   ATAN2
   CEILING or CEIL
   COS
   COT
   DEGREES
   EXP
   FLOOR
   LOG
   LOG10
   PI
   POWER
   RADIANS
   RAND
   SIGN
   SIN
   SQRT
   TAN
   TRUNCATE or TRUNC

Please see the SQL Reference Functions topic for more information.

The SQL engine can now use the numeric 1 (or anything not 0) and 0 to represent TRUE and FALSE, respectively. This is helpful for compatibility with generic front ends, such as those used with the ODBC driver.

There is a new TDBISAMQuery OnQueryError event that can be used to trap SQL errors and decide whether to abort an executing SQL statement or not. If an OnQueryError event handler is not assigned, then any SQL errors will immediately surface as an EDBISAMEngineError exception in the TDBISAMQuery component.

The TDBISAMQuery component now surfaces the OnAlterProgress, OnDataLost, OnIndexProgress, OnOptimizeProgress, OnRepairLog, OnRepairProgress, OnUpgradeLog, OnUpgradeProgress, OnVerifyLog, and OnVerifyProgress events just like the TDBISAMTable component. The only difference is these events are triggered when the corresponding SQL statement is executed instead of being triggered by a method call, including situations where an SQL statement is executed within a script.

There are new OnLoadFromStreamProgress and OnSaveToStreamProgress events in the TDBISAMTable and TDBISAMQuery components for tracking the loading/saving progress of streams.

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