Examples of using the addition update and partial extraction facility for BLOB data

Scalable Database Server, HiRDB Version 8 UAP Development Guide

Organization of this subsection: (1) Addition update of BLOB data; (2) Partial extraction of BLOB data

Multiple files are stored as one BLOB data element.

[Figure]

Explanation

The BLOB data of file 1 is inserted in column C2 of row A in the target table (T1).
The BLOB data of file 2 is added by concatenating the data to column C2 of row A. The same applies when subsequent data is added.

The BLOB data of file 2 is extracted from the BLOB data (column C2) in row A that was stored in Addition update of BLOB data.

[Figure]

Explanation: The SUBSTR scalar function is used to extract data from the starting position (byte (100 1024 + 1) = byte 102401) of the data column for file 2 in column C2 of row A. Only the amount of data equivalent to the length of the data column in file 2 (200 1024 = 204800 bytes) is extracted.