NAME
DL_DataGetNext, CSSM_DL_DataGetNext - Get next data record (CDSA)
SYNOPSIS
# include <cssm.h>
API:
CSSM_RETURN CSSMAPI CSSM_DL_DataGetNext
(CSSM_DL_DB_HANDLE DLDBHandle,
CSSM_HANDLE ResultsHandle,
CSSM_DB_RECORD_ATTRIBUTE_DATA_PTR Attributes,
CSSM_DATA_PTR Data,
CSSM_DB_UNIQUE_RECORD_PTR *UniqueId)
SPI:
CSSM_RETURN CSSMDLI DL_DataGetNext
(CSSM_DL_DB_HANDLE DLDBHandle,
CSSM_HANDLE ResultsHandle,
CSSM_DB_RECORD_ATTRIBUTE_DATA_PTR Attributes,
CSSM_DATA_PTR Data,
CSSM_DB_UNIQUE_RECORD_PTR *UniqueId)
LIBRARY
Common Security Services Manager library (CDSA$INCSSM300_SHR.EXE)
PARAMETERS
DLDBHandle (input)
The handle pair that describes the add-in data storage
library module to be used to perform this function, and
the open data store from which records were selected by
the initiating query.
ResultsHandle (input)
The handle identifying a set of records retrieved by a query
executed by the CSSM_DL_DataGetFirst() function.
Attributes (optional-input/output)
If the Attributes structure pointer is NULL, no values are
returned.
Otherwise, the DataRecordType, NumberOfAttributes and
AttributeData fields are read. AttributeData must be an
array of NumberOfAttributes CSSM_DB_RECORD_ATTRIBUTE elements.
Only the Info field of each element is used on input. The
AttributeFormat field of the Info field is ignored on input.
On output, a CSSM_DB_RECORD_ATTRIBUTE structure containing a
list of all or the requested attribute values (subset) from
the retrieved record. The SemanticInformation field is set.
For each CSSM_DB_ATTRIBUTE_DATA contained in the AttributeData
array, the NumberOfValues field is set to reflect the size of
the Value array which is allocated by the DL using the
application specified allocators. Each CSSM_DATA in the Value
array will have it's Data field as a pointer to data allocated
using the application specified allocators containing the
attributes value, and have it's Length set to the length of
the value.
All values for an attribute are returned (this could be 0).
All fields in the Info field of the CSSM_DB_ATTRIBUTE_DATA are
left unchanged except for the AttributeFormat field, which is
set to reflect the schema.
Data (optional-input/output)
Data values contained in the referenced memory are ignored
during processing and are overwritten with the retrieved
opaque object. On output, a CSSM_DATA structure containing
the opaque object stored in the retrieved record. If the
pointer is data structure pointer is NULL, the opaque object
is not returned.
UniqueId (output)
If successful and (at least) a record satisfying the query
has been found, then this parameter returns a pointer to a
CSSM_UNIQUE_RECORD_PTR structure containing a unique
identifier associated with the retrieved record. This unique
identifier structure can be used in future references to this
record using this DLDBHandle pairing. It may not be valid for
other DLHandles targeted to this DL module or to other
DBHandles targeted to this data store. If there are no more
records satisfying the query, then this pointer is NULL and
CSSM_DL_DataGetNext() must return CSSM_DL_ENDOFDATA; in this
case a normal termination condition has occurred. The
CSSM_DL_FreeUniqueRecord() must be used to de-allocate this
structure.
DESCRIPTION
This function returns the next data record referenced by the
ResultsHandle. The ResultsHandle references a set of records
selected by an invocation of the DataGetFirst function. The
Attributes parameter can specify a subset of the attributes to be
returned. If Attributes specifies an attribute that is not defined
in the database's meta-information, an error condition is returned.
The record values are returned in the Attributes and Data parameters.
The output buffers for the retrieved record are allocated by this
function using the memory management functions provided during the
module attach operation. The function also returns a unique record
identifier for the return record.
The data storage module supports one of two retrieval models:
transactional or file system scan. The transactional model freezes
the set of records to be retrieved at query initiation. The file
system scan model selects from a potentially changing set of records
during the retrieval process. The EndOfDataStore() function indicates
when all matching records have been retrieved. The caller can
determine which retrieval model is supported by examining the
encapsulated product description for this data storage module. Once
a user has finished using a certain query, it must call
CSSM_DataAbortQuery() for releasing resources that CSSM uses. If all
records satisfying the query have been retrieved, then query is
automatically terminated.
RETURN VALUE
A CSSM_RETURN value indicating success or specifying a particular
error condition. The value CSSM_OK indicates success. All other
values represent an error condition.
ERRORS
Errors are described in the CDSA technical standard. See CDSA.
CSSMERR_DL_ENDOFDATA
CSSMERR_DL_FIELD_SPECIFIED_MULTIPLE
CSSMERR_DL_INCOMPATIBLE_FIELD_FORMAT
CSSMERR_DL_INVALID_DB_HANDLE
CSSMERR_DL_INVALID_FIELD_NAME
CSSMERR_DL_INVALID_RECORDTYPE
CSSMERR_DL_INVALID_RECORD_UID
CSSMERR_DL_INVALID_RESULTS_HANDLE
SEE ALSO
Books
Intel CDSA Application Developer's Guide (see CDSA)
Other Help Topics
Functions for the CSSM API:
CSSM_DL_DataGetFirst
CSSM_DL_DataAbortQuery
Functions for the DL SPI:
DL_DataGetFirst
DL_DataAbortQuery