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2.13 Triggers

This display results when:

  • An existing trigger has been chosen for review.
  • A new trigger is to be added

     
    DC@P700103                 Define / Change a Trigger                   
                                                                           
                                                                           
     File      : XXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX       
     Field     : XXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX       
                                                                           
     Order to process / source  . . . . . 999 / DATA DICTIONARY            
     User description of trigger  . . . . _________________________        
     Trigger Function Name  . . . . . . . _______                          
                                                       Before     After    
     Trigger Point(s) . . . . . . . . . . Open                           
                                          Close                          
                                          Read                           
                                          Insert                         
                                          Update                         
                                          Delete                         
                                                                           
                           And/Or Field      Op   Field/Literal            
     Trigger When . . . . .        ______  _  ___________________      
                              __  _____  _  ___________________   +  
                                                                           
                                                                           
     Fnn=Help  Fnn=Exit  Fnn=Cancel  Fnn=Messages                          
     

     |
    Note that file name is only displayed when working at file level. Change and Delete command keys are only enabled when displaying an existing check.
     
    If an existing trigger is being reviewed then the CHANGE key can be used to place the screen in change mode and the required changes made.
    If an existing trigger is being reviewed then the DELETE key can be used to delete the trigger. Note that the delete is immediate. No confirmation is required.
    If a new trigger is being added then the screen will be presented initially with default values. Change as required and press Enter to complete specification of the trigger.
    Input Options
    These input options apply to a trigger:
    Order to Process
    Mandatory, but always prefilled to <highest order number + 10>. Triggers are performed (and displayed) in the sequence of these order numbers (within the trigger level). Order numbers must be unique within the trigger level.
    For instance, TRIG04, TRIG01, TRIG02, TRIG05, TRIG03 would be performed.

    Trigger

    Level

    Order To Process

    TRIG01

    Dictionary

    100

    TRIG02

    Dictionary

    200

    TRIG03

    File

    20

    TRIG04

    Dictionary

    50

    TRIG05

    File

    10

     |
    Source
    Output field. Indicates the source or level at which the trigger applies.
    User Description of Trigger
    Mandatory. Enter a brief description of the trigger to aid other users in understanding its purpose.
    Trigger Function Name
    Mandatory. Enter the name of the trigger function which will be called when the trigger conditions are satisfied. The named function must be defined with the TRIGGER parameter on the FUNCTION command. (Refer to the FUNCTION command in the Technical Reference Guide for details).
    Trigger Points
    At least one point where the function is to be triggered must be entered (by entering a "Y" at the required point).
    Trigger When
    Optional. If no test conditions are specified the trigger will be unconditionally invoked.
    Rules for entering conditions are as follows:
  • Operations allowed are:

    GT 

    Greater than

    GE 

    Greater than or equal to

    LT 

    Less than

    LE 

    Less than or equal to

    EQ 

    Equal to

    NE 

    Not equal to

    REF

    Refers to

  • All operation codes can be suffixed by a "P" indicating that the previous value of the nominated field should be used. Such conditions are only valid for "Update" operations. Also Part 2 of the condition must not be a literal if this type of operation code is used.
  • No conditions are allowed if "Open" or "Close" are used.
  • The "REF" operation code is only valid for "Insert", "Update" and "Read" operations.
  • If the trigger is defined at dictionary level, the conditions can only involve the field to which the trigger is being linked.
  • If the trigger is defined at the file level, the conditions can involve any other real or virtual fields in the file to which the trigger is being linked.

Examples
Trigger field:

Name

Type

Len

Dec

SALARY

P

12

2

 |
 
Trigger function:

Name

Function

Trigger Before

Points After

Comments

TRGFN1

Open

 

 

Call trigger function TRGFN1 following an insert or update of field SALARY, or before a delete of field SALARY. Note that no conditions have been applied to this trigger.

 

Close

 

 

 

 

Read

 

 

 

 

Insert

 

Y

 

 

Update

 

Y

 

 

Delete

Y

 

 

 |
Refer to Trigger Functions for full details and examples.
 
 
 
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