What should I do about my dog going in the trash?

Today, I went out to run a few errands and my dog is a Shih tzu/Maltese mix. So, I decided to be nice to her and leave her off of her leash but I totally forgot that she likes to dig in things. When I came back, trash was all over the place, but there was nothing in it that she could eat (thank goodness) She doesn't do this only when I leave, she also does it around the house if I leave all of the trashcans down. I want to be able to let her have freedom but I will need for her to stop going in in west Philadelphia born and raised On the playground where I spent most of my days Chilling out, maxing, relaxing all cool And all shooting some b-ball outside of the school When a couple of guys, they were up to no good Started making trouble in my neighbourhood I got in one little fight and my mom got scared And said "You're moving with your auntie and uncle in Bel-air" I whistled for a cab and when it came near the License plate said "fresh" and had a dice in the mirror If anything I could say that this cab was rare But I thought nah, forget it, yo homes to Bel-air! I pulled up to a house about seven or eight And I yelled to the cabby "Yo, homes smell you later!" Looked at my kingdom I was finally there To sit on my throne as the prince of Bel-air.