JET_ENUMCOLUMN Structure

Artikkel
05/31/2022

Applies to: Windows | Windows Server

JET_ENUMCOLUMN Structure

The JET_ENUMCOLUMN structure enumerates the column values of a record when the JetEnumerateColumns function is used. JetEnumerateColumns returns an array of JET_ENUMCOLUMN structures. The array is returned in memory that is allocated using the realloc compatible callback that was supplied to that API.

    typedef struct {
      JET_COLUMNID columnid;
      JET_ERR err;
      union {
        struct {
          unsigned long cEnumColumnValue;
          JET_ENUMCOLUMNVALUE rgEnumColumnValue;
        };
        struct {
          unsigned long cbData;
          void* pvData;
        };
      };
    } JET_ENUMCOLUMN;

Members

columnid

The column ID that was enumerated.

err

The column status code that results from the enumeration of the column.

Error Codes	Meaning
JET_errBadColumnId	The column ID is outside the legal limits of a column ID.
JET_errColumnNotFound	The column described by the column ID does not exist in the table.
JET_wrnColumnNull	All values for this column are NULL.
JET_wrnColumnPresent	JET_bitEnumeratePresenceOnly was specified and at least one non-NULL column value would have been returned for this column.
JET_wrnColumnSingleValue	JET_bitEnumerateCompressOutput was specified and exactly one non-NULL column value has been returned for this column. As a result, the compressed form of JET_ENUMCOLUMN has been returned. See JET_ENUMCOLUMN for more information.
JET_wrnColumnSkipped	The column ID in the JET_ENUMCOLUMNID struct corresponding to this JET_ENUMCOLUMN struct was zero.

cEnumColumnValue

The array of column values that was enumerated for the column. The output buffer is returned in memory that was allocated using the realloc compatible callback that was supplied to JetEnumerateColumns.

This output buffer is used when the column status code is not equal to JET_wrnColumnSingleValue. For more information, see JetEnumerateColumns.

This is returned if "err != JET_wrnColumnSingleValue".

rgEnumColumnValue

This output buffer is used when the column status code is not equal to JET_wrnColumnSingleValue. For more information, see JetEnumerateColumns.

This is returned if "err != JET_wrnColumnSingleValue".

cbData

The column value that was enumerated for the column.

The output buffer is returned in memory that was allocated using the realloc compatible callback that was supplied to JetEnumerateColumns.

This output buffer is only used when the column status code is JET_wrnColumnSingleValue. For more information, see JetEnumerateColumns.

This is returned if "err == JET_wrnColumnSingleValue".

pvData

The column value that was enumerated for the column.

The output buffer is returned in memory that was allocated using the realloc compatible callback that was supplied to JetEnumerateColumns.

This output buffer is only used when the column status code is JET_wrnColumnSingleValue. For more information, see JetEnumerateColumns.

This is returned if "err == JET_wrnColumnSingleValue".

Requirements

Requirement	Value
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.

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JET_ENUMCOLUMN Structure