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JetIndexRecordCount Function

Windows

Last modified: January 09, 2012

Applies to: Windows | Windows Server

The JetIndexRecordCount function counts the number of entries in the current index from the current position forward. The current position is included in the count. The count can be greater than the total number of records in the table if the current index is over a multi-valued column and instances of the column have multiple-values. If the table is empty, then 0 will be returned for the count.

JET_ERR JET_API JetIndexRecordCount(
  __in          JET_SESID sesid,
  __in          JET_TABLEID tableid,
  __out         unsigned long* pcrec,
  __in          unsigned long crecMax
);

Parameters

sesid

The session to use for this call.

tableid

The cursor to use for this call.

pcrec

The pointer to an unsigned long value to receive the count.

crecMax

The maximum number of records to count. A crecMax value of 0 indicates that the count is unlimited.

Return Value

This function returns the JET_ERR datatype with one of the following return codes. For more information about the possible ESE errors, see Extensible Storage Engine Errors and Error Handling Parameters.

Return code

Description

JET_errSuccess

The operation completed successfully.

JET_errClientRequestToStopJetService

The operation cannot complete because all activity on the instance that is associated with the session has ceased as a result of a call to JetStopService.

JET_errInstanceUnavailable

The operation cannot complete because the instance that is associated with the session encountered a fatal error that requires that access to all data be revoked to protect the integrity of that data.

Windows XP:  This return value is introduced in Windows XP.

JET_errNoCurrentRecord

The cursor is not currently on a record and the table is not empty.

Windows XP, Windows Server 2003, Windows 2000 Server, and Windows 2000 Professional:  If the cursor is positioned on an empty index or index range then JetIndexRecordCount erroneously returns JET_errNoCurrentRecord.

JET_errNotInitialized

The operation cannot complete because the instance that is associated with the session has not yet been initialized.

JET_errRestoreInProgress

The operation cannot complete because a restore operation is in progress on the instance that is associated with the session.

JET_errSessionSharingViolation

The same session cannot be used for more than one thread at the same time.

Windows XP:  This return value is introduced in Windows XP.

JET_errTermInProgress

The operation cannot complete because the instance that is associated with the session is being shut down.

If this function succeeds, the exact number of index entries including the current position and up to crecMax (if it is not 0), is returned in the unsigned long pointed to by pcrec.

If this function fails, no changes are made to memory allocated at precpos.

Remarks

If the table is not empty, then the cursor should be positioned onto the record from which to begin the count. The count will include this record, and count forward up to the given limit in crecMax. If crecMax is 0 then the operation will continue counting until the end of the index.

Index ranges can be used to construct artificial end-of-index limitations for the count. In this way, subranges of an index can be counted exactly. The cursor should be positioned to the first row in the range. The end of the range key should be made and then JetSetIndexRange should be used to set the upper range, either inclusively or exclusively. Lastly, JetIndexRecordCount should be called to exactly count the range.

JetIndexRecordCount obeys transaction semantics and returns a count that is accurate for this particular session in its current transactional state.

JetIndexRecordCount accesses index leaf pages in order to exactly count entries. Consequently, it can perform a great deal of I/O and can be slow. The crecMax limitation should be used to prevent excessive load. If a range is large, then it might be possible to count the range in an approximated fashion using JetGetRecordPosition.

Windows XP, Windows Server 2003, Windows 2000 Server, and Windows 2000 Professional:  If the cursor is positioned on an empty index or index range then JetIndexRecordCount erroneously returns JET_errNoCurrentRecord rather than returning a record count of zero. The application should check to see if the index or index range is empty in this case.

Requirements

Client

Requires Windows Vista, Windows XP, or Windows 2000 Professional.

Server

Requires Windows Server 2008, Windows Server 2003, or Windows 2000 Server.

Header

Declared in Esent.h.

Library

Use ESENT.lib.

DLL

Requires ESENT.dll.

See Also

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