Description File Examples

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The sample description files shown in this section describe a data file. This data file has a page size of 512 bytes and 2 keys. The fixed-length portion of the record is 98 bytes long. The file allows variable-length records but does not use blank truncation.

The file uses data compression, allows for Variable-tail Allocation Tables (VATs), and has the free space threshold set to 20 percent. The MicroKernel Database Engine preallocates 100 pages, or 51,200 bytes, when it creates the file. The file has two keys: Key 0 and Key 1. Key 0 is a segmented key with two segments.

In Figure A-1 , both keys use the same ACS file name (UPPER.ALT). In Figure A-2 , both keys use the same country ID (-1) and code page ID (-1). In Figure A-3 , Key 0 and Key 1 use different ACS file names (LOWER.ALT and UPPER.ALT, respectively). In Figure A-4 , the file has no keys except the system-defined key used for logging.

 
Figure A-1 Sample Description File Using Alternate Collating Sequence File Name

 
Figure A-2 Sample Description File Using Alternate Collating Sequence ID

 
Figure A-3 Sample Description File Using Alternate Collating Sequence File Name
on a Key Segment

 
Figure A-4 Sample Description File Using System-Defined Key for Logging