HEPDB keys

In order to minimize the disk-memory transfers and to permit a tight control of the whole system, a few general standard keys have been defined. The HEPDB package assumes that all key vectors consist of at least 10 keys. These keys are defined as shown in table [more info].

 +-----------------------------System-keys------------------------------+
 +-Key-number-----------+-Meaning--------------------+-Parameter--------+
 +----------------------+----------------------------+------------------+
 +-1--------------------+-serial-number--------------+-IDHKSN--+
 +-2--------------------+-pointer--------------------+-IDHPTR--+
 +-3--------------------+-flags----------------------+-IDHFLG--+
 +-4--------------------+-insertion-time-------------+-IDHINS--+
 +-5--------------------+-reserved-------------------+------------------+
 +----------------------+---Special-User-keys--------+------------------+
 | 6                    | unique source identifier   | IDHUSI  |
 +-7--------------------+-software-reference-number--+-IDHSRN--+
 +-8--------------------+-reserved-------------------+------------------+
 +----------------------+----------------------------+------------------+
 +-9--------------------+-reserved-------------------+------------------+
 +-10-------------------+-reserved-------------------+------------------+
 +---------Validity-range-pairs-(Repeated-NPAIR-times)---------+
 +-11-------------------+-start-range-1--------------+------------------+
 +-12-------------------+-end-range-1----------------+------------------+
 +---------------Normal-user-keys-(up-to-RZ-limit-of-100)---------------+
 | 11+NPAIR*2  | first normal user key      |                  |
 +-12+NPAIR*2--+-second-normal-user-key-----+------------------+
 +----------------------+----------------------------+------------------+
Table:  HEPDB keys
 

[table-keys]

The system keys should not be touched by the user or application program. The normal user keys may contain any information.

After the standard keys come a number of key pairs. The number of pairs is a database constant. For example, the L3 collaboration uses only one key pair, the start and end times for which a database object is valid. The OPAL collaboration uses 3 key pairs - the start and end experiment, run and event number for which a database object is valid.

Additional keys, the so-called user keys, can be declared by the user (within the overall RZ [bib-ZEBRARZ] limit of 100 keys). Their role will become more transparent when reviewing the functionality of the storage and retrieval of data objects, described below.