This COBOL system supports more than one type of indexed file. The tables
below illustrate the different types available and the features that they
support.
|
Supports Files Logically >4 Gb |
Fast Updates on Files with Multiple Duplicate Keys |
Maximum Occurrences of Duplicate Key Value |
Support for Variable Length Records and Compression |
Separate Index File |
| IDXFORMAT"1" |
不可 |
不可 |
65535 |
不可 |
Yes |
| IDXFORMAT"2" |
不可 |
不可 |
65535 |
不可 |
Yes |
| IDXFORMAT"3" |
不可 |
不可 |
65535 |
Yes |
Yes |
| IDXFORMAT"4" |
不可 |
Yes |
4 G |
Yes |
Yes |
| IDXFORMAT"8" |
Yes |
Yes |
4 G |
Yes |
不可 |
Table 1: Indexed Files - Features Supported
|
Duplicate Occurrence Records |
Data Record Alignment |
File Pointer Size (bytes) |
Residue Length Field |
Index Node Includes Record Header |
| IDXFORMAT"1" |
不可 |
1 |
4 |
n/a |
不可 |
| IDXFORMAT"2" |
不可 |
1 |
4 |
n/a |
不可 |
| IDXFORMAT"3" |
不可 |
4 |
4 |
2 |
不可 |
| IDXFORMAT"4" |
Yes |
4 |
4 |
2 |
不可 |
| IDXFORMAT"8" |
Yes |
8 |
6 |
4 |
Yes |
Table 2: Indexed Files - Physical Characteristics