Explain floating maps with illustration.
CICS Interview Questions
(Continued from previous question...)
Explain floating maps with illustration.
Maps which can positioon themselves relative to the previous maps on the screen or page are known as the floating maps. For this you have to use special positional operands to LINE and COLUMN parameters of the BMS macro definition. They are SAME, NEXT. Actually this floating map concept is there only in Full BMS where as it is not available in Min. or Standard BMS macros. RECEIVE MAP is not recommended in the case of floating maps. Hence these maps are normally used to send information such as selected records from a database to screen but not for data entry. A mapset can contain more than one map in it, you may use all these maps to build a screen. In that case there are two ways to send these maps on to the screen.
i) Use separate SEND MAP commands one for each map involved. or
ii) Use ACCUM operand along with SEND MAP command and while sending really on to the screen use SEND PAGE to display them at one shot. The second one is called cumulative mapping scheme where you also can use foating maps.
Let's take a situation where you have to build a screen like this
HEADER MAP (no. of A gr. employs)
DETAIL MAP ( employee list)
TRAILER MAP (Press a key to continue ...)
Under such situations whatever the detail map needed that is to be displayed again and again to display all the information one screenful at a time. In this floating map concept helps.
Code the map like this
M1 DFHMDI... HEADER=YES, JUSTIFY=FIRST .....
M2 DFHMDI........LINE=NEXT ......
M3 DFHMDI.......TRAILER = YES, JUSTIFY=LAST ......
Here M2 is detail map, which is coded as floating map. Procedure:
EVERY TIME using cumulative map technique send header (first) and followed by detail map next into a page buffer once the page is full an overflow occurs by using CICS HANDLE OVERFLOW command send first trailer map then header map (This will do two things a ) it sends previous map on to the screen b) starts fresh page buffer). Repeated this until no more records to be retrieved. Here M2 is the one which hokls the record values read from the file.
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