How to implement check box in ionic 3 with firebase

Ionic Framework ionic-v3
1

Hello,
I’m practicing ionic 3 with firebase, I’m trying to get check box values in ionic 3 and save them in firebase database. can anyone have suggestions how to generate variables and access them with ngModel to get multiple selecteed values.

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See:

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I have doubt on creating and accessing it in component . i am not able to use multiple check boxes selection and save it to firebase