How to show Sqlite Triggers Raise message in toast-CodePudding

I'm trying to use sqlite trigger before inserting concept for validation in android studio. I'm using 3 fields - farmer_id, farmer_name, father_name and if farmer_name is empty am trying to show an error message as "Farmer Name is mandatory". So I used trigger coding as below in android studio

String farmer_insert_trigger = "CREATE TRIGGER insert_validation"  
            "BEFORE INSERT on farmer_det"  
            "BEGIN SELECT CASE WHEN new.farmer_name IS '' THEN"  
            "RAISE(ABORT,'Farmer Name is mandatory')"  
            "end;"  
            "end;";
public void createTriggers() {
        SQLiteDatabase db = this.getWritableDatabase();
        db.execSQL(farmer_insert_trigger);
    }

when I hit "Submit" button to show the error message as "Farmer Name is mandatory" am getting the error message as "near "SELECT":syntax error (code 1);, while compliling CREATE Triger...". Below is my button click event.

btn.setOnClickListener(v->{
            String farmerID = farmer_id.getText().toString();
            String farmerName = farmer_name.getText().toString();
            String fatherName = father_name.getText().toString();

            try {
                // Execute insert function
                dbHandler.createTriggers();
            } catch (SQLiteConstraintException e) {
                Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_SHORT).show();
            } catch (Exception e) {
                // Just in case the above doesn't catch it
                Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_SHORT).show();
            }        
        });

Did I missed any syntax while creating trigger.

CodePudding user response：

I believe that you are missing spaces where they are required/needed.

Try :-

String farmer_insert_trigger = "CREATE TRIGGER insert_validation /*SPACE*/"  
            "BEFORE INSERT on farmer_det /*SPACE*/"  
            "BEGIN SELECT CASE WHEN new.farmer_name IS '' THEN /*SPACE*/"  
            "RAISE(ABORT,'Farmer Name is mandatory')"  
            "end;"  
            "end;";

Obviously comments /*SPACE*/ not needed.

CodePudding user response：

You can check if a String is empty from program directly like this :

btn.setOnClickListener(v->{
        String farmerID = farmer_id.getText().toString();
        String farmerName = farmer_name.getText().toString();
        String fatherName = father_name.getText().toString();

        if (farmerName.equals("")) {
                Toast.makeText(getApplicationContext(), "Farmer Name is mandatory", Toast.LENGTH_LONG).show();
            } else {
                // Execute insert function
            }        
    });

The program can compile faster because you don't need to check the database and the code is simpler.