DAS

Description

DAS marks database segments as "deleted", making the segment storage space available to other programs. Deleted segments cannot be recovered.

Parameters

das(file, dbsl)

Name	Type	Caption	Length	Value range
FILE *	str	Input file name	1 -
DBSL *	List[int]	Segment(s) to delete	1 -

* Required parameter

Parameter descriptions

FILE

Specifies the name of the PCIDSK file containing segments to be deleted.

DBSL

Specifies the segments to delete.

Details

DAS deletes a specified set of database segments (DBSL) from a PCIDSK file (FILE). The space used by the deleted segments is made available for new segments. DAS does not physically delete the segment or the data stored on it; it simply marks the segment as "deleted". This makes the segment inaccessible to the user, but allows other tasks to create new segments that overwrite the deleted segment.

To permanently delete a segment, run PCIMOD with PCIOP set to "COM" to compress the space.

Locked segments (especially the georeferencing segment, which is usually the first segment on the file) cannot be deleted.

Deleted segments cannot be recovered.

Example

Delete a large vector segment, and immediately recover the disk space.

from pci.das import das

file='irvine.pix'
dbsl=[25]
das(file, dbsl)

pciop='COM'               #Compress deleted segments
pcival=[]
report='OFF'              #So that PCIMOD does not prompt
monitor=''
pcimod(file, pciop, pcival, report, monitor)