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void ReadLongOrLob( saLongOrLobReader_t
fnReader, size_t nReaderWantedPieceSize, void
Starts reading of Long or BLob(CLob) value using user defined callback.
fnReader. The name of user function used for Long or BLob(CLob) data reading. The function must have syntax declared by saLongOrLobReader_t typedef .
nReaderWantedPieceSize. Size of piece of data user want to get to callback function.
pAddData. Additional data, passed to callback function.
After a command execution all output parameters are updated by their values, including Long and BLob(CLob) parameters. If you want to control piecewise reading of Long or BLob(CLob) data you should do the following:
Note, that if the command has result set(s) (it is possible in some servers, see Server specific notes ) then output parameters are available only after all result sets are completely processed using SACommand::FetchNext method.
ReadLongOrLob method will repeatedly call user defined function:
void <function Name>(SAPieceType_t
User defined function has the following parameters:
ePieceType. Parameter passed to the function from SQLAPI++ Library mechanisms. It defines which piece of data value was read. Can be one of the next SAPieceType_t enum values:
pBuf. Pointer to the buffer that contains the data block read from database.
nLen. The actual size of data in buffer pBuf.
nBlobSize. A size of whole Long or BLob(CLob) parameter (if DBMS server allows to know it before whole parameter was read; otherwise 0).
pAddData. An additional data user want to pass to the function.
To get more information about reading Long and BLob(CLob) data see Query examples - Step 6.
Server specific notes
See Server specific information concerning your SQL server.
Problems and Questions
If you haven't found the answer to your questions or have some problems on using the Library, please, send e-mail to email@example.com.