The different types of Data Areas are general data area, local data area, group data area, pip (program initialization parameter data area) data area.
*General Data Area - It can be created by user implicitely or explicitly
It can be referred by any other jobs.
It can be associated with a library.
It can be created, deleted by the user.
* Local Data Area - It can not be referred by any other job.
It is automatically created and deleted by the system.
It is not associated with any library.
*Group Data Area - It is automatically created and deleted by the system We can access the group data area value through clp.
It is meant for group jobs.
*Pip Data Area - It is meant for pre start jobs.
By using keyword SFLRCDNBR.
To create the replica from the original object.
Defining a field as a key in physical file. Hence we can access records through the key field.
Physical file nothing but a table contains a only one record format in which we can describe the field definitions and descriptions.
Using COMIT operation. Makes all changes to the files that have been specified in output operation since the previous COMIT or the begining of operations under commitment control(if there has been no previous COMIT or ROLBK operation).
CA: - It does not retains the value into the buffer memory. CF: - It retains the value into the buffer memory.
*ENTRY PLIST PARM
Logical which uses fields from two or more physical files.
PLIST, CALL, TFRCTL
Using Single statement.
SELECT * FROM FILE1, FILE2
WHERE FILE1.FLD1 = FILE2.FLD1
Using PARM keyword.
Everything on the AS/400 System that can be stored and retrieved is contained in the object.
The result is same as if you had specified ND.
V4R2 (Version @0 Release @0)
Yes. by using CONCAT keyword
With the help of Validity check key words VALUE, RANGE, COMP
There are 7 Specs in RPG they are H, F, E, L, I, C & O.
With the help of 'IN' opcode, we can access the data area record in to the program.
It can be in Arrival & Keyed sequence.
It only provides logical view based on the physical file. This is also called as regular logical file.
Data area is a storage area to store limited information.
Example: a new and unique customer number is generated whenever a new customer is added to customer master file. Data area keeps track of last record added and add 1 to it. Through program we can access new customer number.
Distribution Data Management is a function of the OS/400 that allows an application program or user on one system to use database files stored on remote system.
It is used to execute a single CL command within the RPG program.
Sets on the modified Data Tag of the field. The Data Tag detect whether the field has been changed as a result of user input.
If you specify the letter ' U ' at column 73-74, you need to be open and close files explicitly in a RPG program.
Specify an indicator in position 33-34 of F specification.
It is the most desirable method in building a real time applications. We can use at all the times.
4 Types they are Entry, Menu, Information & List Display.
To define & name the cursor & specify rows to be fetched.
Report line, Filler line & Sample line.
L1 to L9 used to identify certain fields on control fields and then used to condition which operations are to be processed at detail or total calculation or output time.
CHAR, NUMERIC and LOGICAL
DR - Define Record, CLC - Change Line for Continuation, CLR - Change Line for Record, SD - Create Sample Data, VF - View Fields, NP - New Page, DC - Define Constants, DF - Define Fields, CF - Centre Fields & SP - Space Fields evenly.
Put 'N' in position 53 of C specs.
Write & Read.
DSPDBR (Display Database Relationship)
Total 40 (15 system and 25 application)
The basic purpose of Overrides is to temporarily change the attributes of a file. So you don't have to create permanent files for every combination of attributes your application might need. Overrides gives you the flexibility to use existing model files and dynamically change their attributes.
Subsystem is nothing but it provides specialized environment to complete the execution of jobs.