what is the difference between adding keys & constraints
into a phisical file
- 6 Answers
- 13140 Views
- HSBC, I also Faced
- E-Mail Answers
Answer Posted / kolla ravi
Primary Key - Unique Key - Key are all possible with DDS.
Either a primary or a Unique key as required can be setup
with UNIQUE keyword at file level in DDS.These keys Do not
allow any two records with same keys.
When UNIQUE is not used then FIFO or LIFO may be used. When
nothing is specified it is understood to be FIFO.
All these need Key fields to be specified.
And in addition to this whether primary/unique or just a
key, a key field dictates the order of retrieval of records
when programs read the files.
All these what we spoke above is done through DDS. That
is : all these stay right within the object.
On the other hand it is possible to setup Constraints
externally. These being Primary/Unique/Referetinal/Check.
Once these are defined they can be controlled Externally by
enabling, Disabling or removing them on the files for which
they are defined.In this context it is worth while
understanding various states of constraints and Upd/delete
rules in this context.
| Is This Answer Correct ? | 0 Yes | 1 No |
Post New Answer View All Answers
Suppose I have a pf,it contains 5 members,how to access particular member data from logical file ?and what is the use of member in pf?
In a CL Program after executing a SQL SP how to receive a Output value from the SP. Just to make it clear I am sending 2 input and 1 output parameter to the SQL Stored Procedure. Now while receiving it output parm it is failing.
I have physical file with 100 records,there is no any duplicate records in this pf.based on this pf one logical file I have used.but this lf is viewing only 80 records only of that pf?what is the reason for this?
When we create a pf and did not fill up maint parameter, then by default which access path will the system take & why?
How to read a pf in reverse(from last record to first) using cl?
How to retrieve a physical file after deleting that?
How to update physical file using logical file with example?
What is the difference between access path and open data path?
What is FORMAT keyword and its use?
What is the batch job?
There is one string as A B C and wanted to display string as Shri A Shri B Shri C, how we can do this in sql? If we have around 100 values in string like this, each value should be displayed with initials as Shri.
What is the interactive job?
How many maximum record format a logical file have?
What is the use of member in pf?
How to index LF by relative record no (RRN)
