db.enable_counts() method

[simonw]

Following #212 it would be useful if there was a utility method for enabling counts for ALL tables in a database:

db.enable_counts()

Open question: should this setup triggers for virtual tables such as FTS tables? Could that break things?

[simonw]

I'm going to skip virtual tables, which I can identify using this property:

sqlite-utils/sqlite_utils/db.py

Lines 720 to 726 in 1cad7fa

	@property
	def virtual_table_using(self):
	"Returns type of virtual table or None if this is not a virtual table"
	match = _virtual_table_using_re.match(self.schema)
	if match is None:
	return None
	return match.groupdict()["using"].upper()

[simonw]

I got this error while prototyping this:

too many levels of trigger recursion

It looks like that's because SQLite doesn't like triggers on a table that themselves then update that table - so I'm going to exclude the _counts table from this mechanism.