DbiTruncateBlob

C syntax

DBIResult DBIFN DbiTruncateBlob (hCursor, pRecBuf, iField, iLen);

Delphi syntax

function DbiTruncateBlob (hCursor: hDBICur; pRecBuf: Pointer; iField: Word; iLen: Longint): DBIResult stdcall;

Description

DbiTruncateBlob is used to shorten the size of the contents of a BLOB field, or to delete the contents of a BLOB field from the record, by shortening it to zero.

Parameters

hCursor Type: hDBICur (Input)
Specifies the cursor handle.

pRecBuf Type: pBYTE (Input)
Pointer to the record buffer.

iField Type: UINT16 (Input)
Specifies the ordinal number of BLOB field within the record buffer.

iLen Type: UINT32 (Input)
Specifies the new shorter length of the BLOB. If zero is specified, the whole BLOB is truncated.

Usage

This is the only way to delete a BLOB without deleting the entire record.

Standard, Access: It is advisable to lock the record before opening the BLOB in read-write mode to ensure that another client application does not lock the record.

Prerequisites

The current record must contain a BLOB field. The BLOB field must be open in dbiREADWRITE mode by a call to DbiOpenBlob.

Completion state

After shortening the BLOB field, DbiModifyRecord must be called to post the altered record to the table.

DbiResult	Meaning
DBIERR_NONE	The BLOB field was successfully truncated.
DBIERR_BLOBNOTOPENED	The specified BLOB field was not opened via a call to DbiOpenBlob.
DBIERR_INVALIDBLOBHANDLE	The BLOB handle supplied in the record buffer is invalid.
DBIERR_NOTABLOB	The specified field number does not correspond to a BLOB field.
DBIERR_INVALIDBLOBOFFSET	The specified iOffSet is greater than the length of the BLOB field.
DBIERR_READONLYFLD	The BLOB field was opened in dbiREADONLY mode and cannot be modified.