Fujitsu UDS/SQL V2.5 Manual Do Utilizador

SSL

132

  

 U929-J-Z125-9-76

To find the physical address of records and associated tables, UDS/SQL can always make 
use of an additional identifier, the database key value, which never changes during the life 
of a record in the database. 

A record type consists of a number of records which are consecutively numbered. The 
record types are also numbered. The record sequence number (RSQ) and record type 
reference (REC-REF) are combined to form the database key value of the record.
The database key is thus an identifier that uniquely identifies each record contained in the 
database.

The structure of the database key value varies, depending on whether the database page 
length is 2048 bytes or 4000/8096 bytes. 

Figure 28: Structure of a database key value if the page length is 2048 bytes 

Figure 29: Structure of a database key value if the page length is 4000 or 8096 bytes

The following applies to the value range for a record reference number (REC-REF):

–

1 

≤ REC-REF ≤ 254 for databases with a 2048-byte page length

–

1 

≤ REC-REF ≤ 2

15

-1 for databases with a 4000/8096-byte page length

1 byte

3 bytes

REC-REF

RSQ

REC-REF
RSQ

 = Record reference no.
 = Record sequence no.

2 bytes

2 bytes

REC-REF

RSQ

REC-REF
RSQ

 = Record reference no.
 = Record sequence no.

not used

4 bytes