Random Retrieval of Data

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Hello Community, Is there a way to randomly retrieve 1 data from the database. which is not bounded by any specific conditions or in any order. Complete random.   Thanks in advance.    
asked
2 answers
5

Hi Abhishek,

You can do this by using a microflow and a java action,

First, retrieve all the objects of an entity and then

You can use the Math.random() JavaScript function in a Java action to generate a random number and sort the list based on this number.

Here are the general steps to do this:

  1. Create a Java action in your Mendix module.
  2. Add a parameter of type List<yourEntity> to the Java action.
  3. Use the following code in the Java action to shuffle the list based on a random number: 
    import java.util.*;

public class YourJavaActionName {
    public static List<yourEntity> shuffleList(List<yourEntity> inputList) {
        List<yourEntity> list = new ArrayList<>(inputList);
        Collections.shuffle(list, new Random(System.currentTimeMillis()));
        return list;
    }
}

     

  4. In your microflow, use a 'Java Action' activity to call the Java action and pass the list of objects you want to shuffle as a parameter.
  5. Use a 'List Operation' activity to retrieve the first object in the shuffled list. You can use the 'Head' function to do this.

Hope it helps!!

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0

You could also do this without a java action.

  • Retrieve all objects
  • Do a count on this list, call it $Count
  • Create a variable of type integer, round(random()*$Count), call it RandomOffset
  • Retrieve objects and select option Custom and set an Offset and Amount of 1
  • Use 'List Operation' to get head of the list of 1
answered