Database Program Translation - Information Systems Reengineering, Integration and Normalization - page 191

The syntax for the algorithm Insert is:

Relational Network

Exec SQL Insert into
Table-T(F1, F2,….Fn)
Values (V1, V2…..Vn)
End-Exec.

Find first N k-1 within Ix k-1 using

ID k-1 .
If return-code ≠ 0
error-exit-1
else
Move V1 to F1
Move V2 to F2
…
Move Vn to Fn
Find first N k within IX k
using ID k
If return-code = 0
error-exit-2
else
Store N k
If set membership between
N k and N k-1 is manual
connect N k to N k-1 .

Relational Operation Deletion
A simple delete-only statement in the network database corresponds to the rela-
tional database delete statement for a given relational schema. The delete-record-N-
only statement has the following properties:

• RemoverecordN k from all set occurrences in which it participates as a member.
• RemovebutdonotdeletealloptionalmembersN k+1 , for each set where N k par-
ticipates as an owner record.
• DonotdeleterecordN k if there are fixed or mandatory members record N k+1 for
each set S where N k participates as an owner record.
The syntax for the algorithm Delete is:

Relational Network

Exec SQL Delete from
Table-T
where F1 = V1
and F2 = V2
and …
and Fn = Vn
End-Exec.

Obtain first N k within IX k
using ID k .
If return-code ≠ 0
error-exit-1
else
Find current N k+1 within S
If return-code = 0
error-exit-2
else