Transaction in CICS has a great importance which is the unit of work performed and is represented by a 4 char TRANS ID. It is linked to one or more programs and once a transaction is initiated, programs that are defined gets executed. At the time of transction definition, these programs needs to be given/linked.
In simple words Transaction is a Unique code to execute any program under CICS. Program can not be invoked directly by the user. Either transaction is required or it should be invoked by an other program.
When a Transaction is invoked, program associated with that is loaded in to storage and a task gets started.
– PCT is checked to see the associated program.
– PPT checks whether the program is in main storage or on disk. If it is on DISK, it loads the program on to main storage.
How to define a new transaction in CICS:
CEDA transaction is used for defining a transaction in CICS. It has many options in the definition screen, most of these options are default and can be set based on any other existing transaction in the same group/application.
Below is the Sample definition:
CEDA DEFine TRANSaction(TRN1) GROUP(APPGROUP) TRANSaction == TRN1 Group == APPGROUP DEScription == TRANSACTION FOR DISPLAYING CUSTOMERS BY ID PROGram == PROG1 TWasize == 00000 0-32767 PROFile = DFHCICST PArtitionset == STAtus == Enabled Enabled | Disabled PRIMedsize :0000 0-65520 TASKDATALoc == Below Below | Any TASKDATAKey == User User | Cics STOrageclear == Yes No | Yes RUnaway == System | 0 | 500-2700000 SHutdown ==Disabled Disabled | Enabled ISolate == Yes Yes | No Brexit == REMOTE ATTRIBUTES DYnamic == No No | Yes ROutable == No No | Yes REMOTESystem == REMOTEName == TRProf == Localq == No | Yes SCHEDULING PRIOrity == 001 0-255 TClass : No No | 1-10 TRANClass == ALIASES ALias == TASKReq = XTRanid = TPName = => XTPname : RECOVERY DTimout = No No | 1-6800 (MMSS) RESTart == No No | Yes SPurge == No No | Yes TPUrge == No No | Yes DUmp == Yes Yes | No TRACe == Yes Yes | No COnfdata == No No | Yes Otstimeout == No No | 0-240000 (HHMMSS) INDOUBT ATTRIBUTES ACtion == Backout Backout | Commit WAIT == Yes Yes | No WAITTime == 00 , 00 , 00 0-99 (Days,Hours,Mins) INdoubt : Backout Backout | Commit | Wait SECURITY TRACe == Yes Yes | No COnfdata == No No | Yes Otstimeout == No No | 0-240000 (HHMMSS) INDOUBT ATTRIBUTES ACtion == Backout Backout | Commit WAIT == Yes Yes | No WAITTime == 00 , 00 , 00 0-99 (Days,Hours,Mins) INdoubt : Backout Backout | Commit | Wait SECURITY RESSec == No No Yes CMdsec == No No Yes Extsec : No No | Yes TRANSec : 01 1-64 RSl : 00 0-24 | Public DEFINITION SIGNATURE DEFinetime : CHANGETime : CHANGEUsrid : CHANGEAGEnt : CSDApi | CSDBatch CHANGEAGRel :
Existing transaction definition can be viewed using CEDA
ex: CEDA VIEW TRAN(TRN2) GROUP(appgroup)
There are CICS supplied transactions which are widely used by CICS admins and users.
Refer these list @ https://www.ibm.com/support/knowledgecenter/en/SSGMCP_5.3.0/com.ibm.cics.ts.systemprogramming.doc/topics/dfha726.html