This MongoDB Drop Collection lesson is for a beginner. Read the short notes, run each example, then change one name or number and run it again.
drop deletes a collection and the documents in it. The database remains.
Check the collection name before you call it.
Example 1: Start here
db.batch.drop() is the shell form.
db = {"learner": [{"name": "Meera"}], "batch": []} # a dictionary; each key has one value
del db["batch"] # remove this name
print(sorted(db)) # a new list, sorted
Example 2: Filter the rows
MongoDB Drop Collection is easier to see as a list of records. The filter keeps every row whose seats value is at least 10.
rows = [{"topic": "MongoDB Drop Collection", "seats": 37}, {"topic": "SQL", "seats": 12}] # a list; the values stay in this order
print([row["topic"] for row in rows if row["seats"] >= 10]) # keep the items that pass the test
Example 3: Update one field
An update changes one field and leaves the rest of the record alone. On a database you would run an UPDATE or an update_one for the same change.
row = {"topic": "MongoDB Drop Collection", "seats": 37} # a dictionary; each key has one value
row["seats"] = row["seats"] + 1 # change this one field
print(row)
Example 4: Count the matches
Counting matches is the idea behind COUNT(*). Here the number 37 appears twice.
rows = [37, 4, 37] # a list; the values stay in this order
print(sum(1 for value in rows if value == 37)) # keep the items that pass the test
db.batch.drop() is the shell form.
