"""Database management."""
from os.path import isfile
+from difflib import Differ
from sqlite3 import connect as sql_connect
from plomtask.misc import HandledException
PATH_DB_SCHEMA = 'scripts/init.sql'
-class DatabaseFile:
+class DatabaseFile: # pylint: disable=too-few-public-methods
"""Represents the sqlite3 database's file."""
def __init__(self, path):
self.path = path
- self.check()
-
- def check(self):
- """Check file exists and is of proper schema."""
- self.exists = isfile(self.path)
- if self.exists:
- self.validate_schema()
+ self._check()
def remake(self):
"""Create tables in self.path file as per PATH_DB_SCHEMA sql file."""
with sql_connect(self.path) as conn:
with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f:
conn.executescript(f.read())
- self.check()
+ self._check()
+
+ def _check(self):
+ """Check file exists and is of proper schema."""
+ self.exists = isfile(self.path)
+ if self.exists:
+ self._validate_schema()
- def validate_schema(self):
+ def _validate_schema(self):
"""Compare found schema with what's stored at PATH_DB_SCHEMA."""
sql_for_schema = 'SELECT sql FROM sqlite_master ORDER BY sql'
- msg_wrong_schema = 'Database has wrong tables schema.'
+ msg_err = 'Database has wrong tables schema. Diff:\n'
with sql_connect(self.path) as conn:
schema_rows = [r[0] for r in conn.execute(sql_for_schema) if r[0]]
retrieved_schema = ';\n'.join(schema_rows) + ';'
with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f:
stored_schema = f.read().rstrip()
if stored_schema != retrieved_schema:
- raise HandledException(msg_wrong_schema)
+ diff_msg = Differ().compare(retrieved_schema.splitlines(),
+ stored_schema.splitlines())
+ raise HandledException(msg_err + '\n'.join(diff_msg))
+
+
+class DatabaseConnection:
+ """A single connection to the database."""
+
+ def __init__(self, db_file: DatabaseFile):
+ self.file = db_file
+ self.conn = sql_connect(self.file.path)
+
+ def commit(self):
+ """Commit SQL transaction."""
+ self.conn.commit()
+
+ def exec(self, code: str, inputs: tuple = ()):
+ """Add commands to SQL transaction."""
+ return self.conn.execute(code, inputs)
+
+ def close(self):
+ """Close DB connection."""
+ self.conn.close()