Answer / venkat

The format of this keyword is:
UNIQUE[(*INCNULL | *EXCNULL)]The parameter is optional. When specified, it determines whether null key values cause duplicates. *INCNULL is the default and indicates to include null values when determining duplicates. *EXCNULL, when specified, indicates to exclude null values when determining duplicates.
When a logical file based on a physical file has the UNIQUE keyword, the physical file member or members cannot have duplicate key values.

When you specify the UNIQUE keyword for a physical or logical file, you must specify the MAINT(*IMMED) parameter value on the Create Physical File (CRTPF) or Create Logical File (CRTLF) command that creates the file. This means that the access path is maintained immediately when changes are made.

If you do not specify the UNIQUE keyword, records with duplicate key values are sequenced in the order you specify. If you specify the FIFO keyword, they are sequenced in first-in first-out order. If you specify the LIFO keyword, they are sequenced in last-in first-out order. If you specify the FCFO keyword, they are sequenced in first-changed first-out order. If you do not specify FIFO, LIFO or FCFO, the order in which the records are sequenced is not guaranteed.

You cannot specify the UNIQUE keyword with the FIFO, LIFO, FCFO, or REFACCPTH keywords.

Example
The following example shows how to specify the UNIQUE keyword for a logical file.

|...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
00010A*
00020A* SAMPLE LOGICAL FILE (CUSMSTL)
00030A*
00040A UNIQUE
00050A R CUSREC PFILE(CUSMSTP)
00060A TEXT('Logical File Master Record')
00070A CUST
00080A NAME
00090A ADDR
00100A K CUST

Answer / ravi kumar

Hi,

Yes. When Pf doesn't contain duplicate records based on key value then we can use UNIQUE keyword in logical file. If pf contain Duplicate values then LF will not compile.


I have tried in this scenario

Answer / sravan

Yes you can use unique key in logical files.

How do you know if a record exists without doing a READ and CHAIN?

6 Answers   IBM,

---

What does Implicit Open means with respect to a file ? What about the Explicit Open?..what are the major differences between these two?

1 Answers   IBM,

---

RPG/400 number of Records present in a physical file using file information data structure FPF001 IP E DISK F KINFDS INFDS1 IINFDS1 DS I *RECORD RECORD Is this coding correct sir,i have given I P E that is I- input,P-primary file,E-externally described. Primary to use RPG logic cycle,is this the correct method because we have to find number of records present using file information data structure in RPG/400 without doing any input/output operations on the file and also without using DSPFD,SQL. If the above coding is correct means,when i compile the program it gets compiled,but if i call the program it does not return anything,i need number of records,please complete the coding sir.

1 Answers   IBM,

---

1.CA(command Atention key)& CF(command Function key) difference with example?Please can any body tell me in real time exp? 2.Can any body tell me some mandatery function keys using while creating any screen with use of SDA-FUNCTION kEYS?

5 Answers   HCL,

---

How can we receive values from a called procedure in CL?

1 Answers   IBM, NTT Data,

---

Can AnyOne tell me how to read join logical file in rpg from starting to end?

2 Answers  

---

Interviewer asked me write down DDS for load all subfile .can anybody write dds

0 Answers  

---

how do u find whether a record is locked or not??/

5 Answers   CTS,

---

what is estimation? and what is the level identifier parameter in PF?

3 Answers   TCS,

---

suppose i i am changing / updating record of subfile and i want to change the record in reverse order . means i want to change the bottom record first and so on through readc . how i do it please any one explain .

4 Answers   CSC,

---

How can we search particular records from the database file in RPG. For example, there are 100 records in the file.i need to retrieve all the records matching/equal to the particular 'NAME' field. How can we do the above using SEARCH criteria other than using the IF cond?

4 Answers   CTS,

---

in which journalling which attributes are necessary

2 Answers   CTS,

---