Table E (File architecture): Difference between revisions

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:[[File architecture Table E fileorg 100|Table E with FILEORG 100]]
:[[File architecture Table E fileorg 100|Table E with FILEORG 100]]




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| File level parameter [[MINLOBE parameter|MINLOBE]] may be set to permit small (200 bytes or less) of data to be stored directly in the record in Table B.
| File level parameter [[MINLOBE parameter|MINLOBE]] may be set to permit small (200 bytes or less) of data to be stored directly in the record in Table B.
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Revision as of 01:07, 12 March 2013

Holds Large Objects (CLOBs and LOBs)


Enabled by reorganizing / CREATEing a file with ESIZE greater than 0, and then defining a field with a datatype of CLOB or BLOB (the file must have an ESIZE for the latter to occur).

Available as of Model 204 V7.1


Summary

Storage and manipulation of Large Objects (LOBs) differs greatly depending on whether FILEORG x'100' is set.

Table E without FILEORG 100
Table E with FILEORG 100



Table Illustrating Differences Without / With x'100'

Function non x'100' x'100'
General space management LOBs require contiguous space
New LOBs are always written starting at EHIGHPG; if ESIZE is reached, Table E is scanned for contiguous space (due to deletes).

Table E can 'fill' even with many available pages if the space is fragmented.
LOBs are stored as a series of chained pages, and new LOBs are written first using those in the reuse queue (due to deletes). Tabl;e E will 'fill' only if all pages are used.
Change a LOB At the time a LOB is first stored, if you expect to subsequently need to increase its size, you will need to reserve the necessary space in the initial add. LOBS may be changes as needed.
Storing small amounts of data in a LOB field Even a single byte of data requires a full page of Table E File level parameter MINLOBE may be set to permit small (200 bytes or less) of data to be stored directly in the record in Table B.