Adds a new function, `cursor.explain`, which acts similiarly to `cursor.execute`, except it prefixes the query with `EXPLAIN QUERY PLAN` (if not already an EXPLAIN query) and returns a string result containing the formatted query plan (formatted similarly to the sqlite3 API).
Also supports writing the query plan to stdout via the query parameter `out='print'`, or returning the tree representation with `out='plan'`, or writing to any bytes writable stream. For the async version, supports both synchronous writes and asynchronous writes, similar to backup.
py
import rqdb
conn = rqdb.connect(['127.0.0.1:4001'])
cursor = conn.cursor()
cursor.execute('CREATE TABLE persons (id INTEGER PRIMARY KEY, uid TEXT UNIQUE NOT NULL, given_name TEXT NOT NULL, family_name TEXT NOT NULL)')
cursor.explain("SELECT id FROM persons WHERE TRIM(given_name || ' ' || family_name) LIKE ?", ('john d%',), out='print')
--SCAN persons
cursor.execute("CREATE INDEX persons_name_idx ON persons(TRIM(given_name || ' ' || family_name) COLLATE NOCASE)")
cursor.explain("SELECT id FROM persons WHERE TRIM(given_name || ' ' || family_name) LIKE ?", ('john d%',), out='print')
--SEARCH persons USING INDEX persons_name_idx (<expr>>? AND <expr><?)