dave boland wrote:
> Being a little paranoid, I like to insure that the db file exists
SQLite automatically creates an empty DB if you try to open
a nonexistent file, so you do not actually need to do anything.
> and what state it is in (unconfigured, so needs to be made
> ready; or ready to accept data (or be read)). How do I do that?
Store a DB version number somewhere. (You can do it like Android and use
PRAGMA user_version, or use an entry in some table.) If the version
number is not high enough, you have to create or update the database.
Do everything in a transaction to prevent a partially-created/updated
database:
conn.isolation_level = None # Python sucks
conn.execute('begin')
with conn: # automatically commits or rolls back the
transaction
version = conn.execute('PRAGMA user_version').fetchone()[0]
if version < 1:
conn.execute('CREATE TABLE foo(bar)')
# ...
conn.execute('PRAGMA user_version = 1')
# optional: updates
if version < 2:
conn.execute('ALTER TABLE foo ADD COLUMN baz')
# ...
conn.execute('PRAGMA user_version = 2')
Regards,
Clemens
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