Reference Table with Dynamic Validation
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- 1 Motivation
- 2 Case Study
- 3 Steps
- 4 Final Effect
- 5 Passing Values Via Rules
- How would you like a field in your window that has a pull down list containing values that are dynamic?
- which is dependent on another table in the database?
- which will select distinct values or group them into unique occurrences if they are not unique?
- easily achieved without coding but some mouse-clicks to setup?
- How would you like a field that has its pull down list populated with values controlled by the value of another field?
- with no source-code change?
- easily done with simple proto SQL phrases?
- You have come to the right place as we shall show you exactly how quick and easy that is done here!
- We are doing this as a prototype for an E-ticketing system.
- We are going to create a Reference to a Table in the database.
- The Reference are created for the field ET_TripBegin (Origins) and ET_TripEnd (Destinations) from table ET_Booking. They will access the Table called ET_Vehicle that is a holder of available routes or schedule trips.
Table and Column Setting for Vehicle
- The ET_TripBegin field Reference is set to Table instead of String. A new Reference 'Departures' is created. You can do that on the fly by right-clicking on it and select Zoom.
Reference Table Validation Setting for TripBegin Field
- The table is selected here and the field chosen is the ET_Departure which becomes distinct origins during pull down.
- You can see the result from the following screen.
Booking Window Result
- It shows all the available origins that the user can choose from.
- Now we shall do the same for the other field which concerns destinations or arrivals.
Table and Column Setting For Booking
- This second field ET_TripEnd will refer the same table. Note that it has an extra duty under Dynamic Validation.
Reference Table Validation for TripEnd Field
- The pull down will show all the arrivals. But we do not want all of them. We just want those that correspond to the origin.
Dynamic Validation SQL Code
- Dynamic Validation allows for SQL injection, where we supply the WHERE clause.
- Here we ask it to access the ET_Vehicle table for records similar to the origin by ensuring similar ET_Departure values.
- @..@ traps the field value in play. We place it within single quotes '@..@' for SQL to take it as a string value.
- We see that only destinations associated with the origin is displayed in the pull down. The selections are pushed to the upper row by a Callout as the pull downs will clear during Save.
Passing Values Via Rules
- You can create a Rule script and assign it to the Callout so that it copies over the values to other fields and refresh: