ENABLE User's Guide

DEVELOPING A DATA BASE
Determining File Size
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| |
| (9) Identifies the index block length in bytes (IBLOCK |
| 512). (Consider increasing this to 4096 bytes.) |
| |
|(10) Creates the named data file ("employee") |
| |
|(11) Restores the file-creation command parameters to their |
| default settings |
| |
|(12) Indicates that the alternate key file is a |
| key-sequenced (K) file. Alternate key files are always |
| key-sequenced files |
| |
|(13) Creates the alternate key file ("employe0") |
| |
|(14) Identifies an alternate key specifier ("dn"), provides |
| the location of this key (KEYOFF 6) in bytes relative |
| to the start of a record, defines the key length |
| (KEYLEN 18) in bytes, and identifies the alternate key |
| file number (FILE 0). (FUP associates this alternate |
| key with the actual alternate key file by means of the |
| ALTFILE command described in note 15.) |
| |
|(15) Identifies the alternate key file ("depend0") |
| associated with "depend" |
| |
|(16) Creates "depend" |
| |
|(17) Creates "depend0," the alternate key file for "depend" |
| |
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Figure 3-10. Sample FUP Source Commands (Continued)
Determining File Size
When DDL writes FUP file-creation commands, it does not include a
command to define the file size. The default file size is one
page (4096 bytes) for the primary extent and one page for each
secondary extent. Each file has 1 primary extent and up to 15
secondary extents that are allocated automatically by the
computer system when they are needed.
These default extent sizes are small. Using them, a
key-sequenced file with records 100 bytes long could store about
320 records. For most applications, you will want to make the
extents larger.
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