ADSCustomizeAOF()

Add or remove records from an existing AOF

Syntax

ADSCustomizeAOF( [<nRecno | aRecNos>] [, <nType>] ) --> nSuccess

Arguments

<nRecno | aRecNos> Can be either a single record number or an array of record numbers to add or delete from the AOF. If omitted, defaults to the current record.

<nType> The type of operation:

ADS_AOF_ADD_RECORD	Add the record to the AOF (set the bit). This is the default operation.
ADS_AOF_REMOVE_RECORD	Remove the record from the AOF (clear the bit).
ADS_AOF_TOGGLE_RECORD	Switch the record into or out of the AOF.

Returns

<nError> ADS error code, or 0 for success.

Description

An Advantage Optimized Filter (AOF) consists of a bitmap of the records in the database. If bit 5 is on, record 5 is considered a visible record. If bit 5 is off, record 5 is not visible. It does not "pass the test". Initially, the bits are set by the Server according to a filter expression from SET FILTER TO or adsSetAOF(). But by using ADSCustomizeAOF() you can add or remove records at will from the visible set. This is useful for tagging records or for refining a result set after the data has been retrieved from the server.

The maximum number of records that can be customized in a single call is 16,383, so <aRecNos> must not be longer than this.

Calls to AdsCustomizeAOF must be made after an application has created a filter with a call to AdsSetAOF. To create a completely empty record set (to which records can be added with calls to AdsCustomizeAOF), use ".F." as the filter expression given to AdsSetAOF. To create a completely full record set (from which records can be removed), use ".T." as the filter expression.

WARNING: Always start with a FULLY optimized AOF! If an application must use a filter expression that is not fully optimized as the starting point for customization, the ADS_RESOLVE_IMMEDIATE option should be used with the call to AdsSetAOF. Otherwise, the dynamic filter resolution that occurs on the server will automatically remove records that have been added through the AdsCustomizeAOF calls. The filter expressions ".T." and ".F." both result in fully optimized AOFs regardless of available indexes.

See ACE.HLP for full details about the Advantage Database Server.

Status

Ready

Compliance

Harbour extension

Platforms

Windows 32-bit

Files

Library is RddAds Header is ads.ch

See Also

• ADSClearAOF()
• ADSEvalAOF()
• ADSGetAOF()
• ADSGetAOFoptLevel()
• ADSIsRecordInAOF()
• ADSRefreshAOF()