HP 3000 Manuals HP 3000 Manuals
Limits
These are some limits on the use of B-Tree indices:
* Key limits
KSAM limits keys up to 255 bytes. TurboIMAGE/XL limits keys to
510 bytes (255 halfwords). TurboIMAGE items are always an even
number of bytes in length, with 2 bytes for internal use. This
means that the maximum TurboIMAGE key that can be indexed is 252
bytes. Attempting to build an index for a master data set whose
key is greater than 252 bytes will not succeed, and will generate
an error message.
* Maximum number of file opens
MPE/iX currently limits a single process to opening a maximum of
1023 files at a time. For a database with 199 sets, 100 of which
are master data sets with B-Tree indices, if all sets are open at
the same time, an additional 100 files will be open.
* Pattern matching
The only types of generic key pattern matching supported are:
=_ search for item values equal to the specified value
<_ search for item values less than specified value
<= search for item values less than or equal to the
specified value
>_ search for item values greater than specified value
>= search for item values greater than or equal to the
specified value
[ ] search for item values between and including two
specified values.
@c search for items with a common prefix.
PK search for items with partial key.
The operator < > for "not equal to" and the range search ( ) are
not supported.