X-Git-Url: https://plomlompom.com/repos/berlin_corona.txt?a=blobdiff_plain;f=plomtask%2Fdb.py;h=df98dd0f130bbd75553b2e628cd739d793e98616;hb=b4a34a415fb31a00ee1e092fcc2a6b5d97edd52a;hp=bd609685096b9d2dbc3dd0b0ea4243ec47904058;hpb=5ced0155ad11f5fb87aaa0848402e95f8ff49acd;p=plomtask diff --git a/plomtask/db.py b/plomtask/db.py index bd60968..df98dd0 100644 --- a/plomtask/db.py +++ b/plomtask/db.py @@ -18,8 +18,9 @@ class UnmigratedDbException(HandledException): """To identify case of unmigrated DB file.""" -class DatabaseFile: # pylint: disable=too-few-public-methods +class DatabaseFile: """Represents the sqlite3 database's file.""" + # pylint: disable=too-few-public-methods def __init__(self, path: str) -> None: self.path = path @@ -38,7 +39,7 @@ class DatabaseFile: # pylint: disable=too-few-public-methods def migrate(cls, path: str) -> DatabaseFile: """Apply migrations from_version to EXPECTED_DB_VERSION.""" migrations = cls._available_migrations() - from_version = cls.get_version_of_db(path) + from_version = cls._get_version_of_db(path) migrations_todo = migrations[from_version+1:] for j, filename in enumerate(migrations_todo): with sql_connect(path) as conn: @@ -54,7 +55,7 @@ class DatabaseFile: # pylint: disable=too-few-public-methods """Check file exists, and is of proper DB version and schema.""" if not isfile(self.path): raise NotFoundException - if self.user_version != EXPECTED_DB_VERSION: + if self._user_version != EXPECTED_DB_VERSION: raise UnmigratedDbException() self._validate_schema() @@ -86,7 +87,7 @@ class DatabaseFile: # pylint: disable=too-few-public-methods return migrations_list @staticmethod - def get_version_of_db(path: str) -> int: + def _get_version_of_db(path: str) -> int: """Get DB user_version, fail if outside expected range.""" sql_for_db_version = 'PRAGMA user_version' with sql_connect(path) as conn: @@ -99,9 +100,11 @@ class DatabaseFile: # pylint: disable=too-few-public-methods return db_version @property - def user_version(self) -> int: + def _user_version(self) -> int: """Get DB user_version.""" - return self.__class__.get_version_of_db(self.path) + # pylint: disable=protected-access + # (since we remain within class) + return self.__class__._get_version_of_db(self.path) def _validate_schema(self) -> None: """Compare found schema with what's stored at PATH_DB_SCHEMA.""" @@ -156,8 +159,7 @@ class DatabaseConnection: """A single connection to the database.""" def __init__(self, db_file: DatabaseFile) -> None: - self.file = db_file - self.conn = sql_connect(self.file.path) + self.conn = sql_connect(db_file.path) def commit(self) -> None: """Commit SQL transaction.""" @@ -167,6 +169,11 @@ class DatabaseConnection: """Add commands to SQL transaction.""" return self.conn.execute(code, inputs) + def exec_on_vals(self, code: str, inputs: tuple[Any, ...]) -> Cursor: + """Wrapper around .exec appending adequate " (?, …)" to code.""" + q_marks_from_values = '(' + ','.join(['?'] * len(inputs)) + ')' + return self.exec(f'{code} {q_marks_from_values}', inputs) + def close(self) -> None: """Close DB connection.""" self.conn.close() @@ -183,8 +190,7 @@ class DatabaseConnection: self.delete_where(table_name, key, target) for row in rows: values = tuple(row[:key_index] + [target] + row[key_index:]) - q_marks = self.__class__.q_marks_from_values(values) - self.exec(f'INSERT INTO {table_name} VALUES {q_marks}', values) + self.exec_on_vals(f'INSERT INTO {table_name} VALUES', values) def row_where(self, table_name: str, key: str, target: int | str) -> list[Row]: @@ -220,11 +226,6 @@ class DatabaseConnection: """Delete from table where key == target.""" self.exec(f'DELETE FROM {table_name} WHERE {key} = ?', (target,)) - @staticmethod - def q_marks_from_values(values: tuple[Any]) -> str: - """Return placeholder to insert values into SQL code.""" - return '(' + ','.join(['?'] * len(values)) + ')' - BaseModelId = TypeVar('BaseModelId', int, str) BaseModelInstance = TypeVar('BaseModelInstance', bound='BaseModel[Any]') @@ -244,16 +245,24 @@ class BaseModel(Generic[BaseModelId]): if isinstance(id_, int) and id_ < 1: msg = f'illegal {self.__class__.__name__} ID, must be >=1: {id_}' raise HandledException(msg) + if isinstance(id_, str) and "" == id_: + msg = f'illegal {self.__class__.__name__} ID, must be non-empty' + raise HandledException(msg) self.id_ = id_ + def __hash__(self) -> int: + hashable = [self.id_] + [getattr(self, name) for name in self.to_save] + for definition in self.to_save_relations: + attr = getattr(self, definition[2]) + hashable += [tuple(rel.id_ for rel in attr)] + for name in self.to_save_versioned: + hashable += [hash(getattr(self, name))] + return hash(tuple(hashable)) + def __eq__(self, other: object) -> bool: if not isinstance(other, self.__class__): return False - to_hash_me = tuple([self.id_] + - [getattr(self, name) for name in self.to_save]) - to_hash_other = tuple([other.id_] + - [getattr(other, name) for name in other.to_save]) - return hash(to_hash_me) == hash(to_hash_other) + return hash(self) == hash(other) def __lt__(self, other: Any) -> bool: if not isinstance(other, self.__class__): @@ -263,9 +272,11 @@ class BaseModel(Generic[BaseModelId]): assert isinstance(other.id_, int) return self.id_ < other.id_ + # cache management + @classmethod - def get_cached(cls: type[BaseModelInstance], - id_: BaseModelId) -> BaseModelInstance | None: + def _get_cached(cls: type[BaseModelInstance], + id_: BaseModelId) -> BaseModelInstance | None: """Get object of id_ from class's cache, or None if not found.""" # pylint: disable=consider-iterating-dictionary cache = cls.get_cache() @@ -302,6 +313,8 @@ class BaseModel(Generic[BaseModelId]): cache = self.__class__.get_cache() del cache[self.id_] + # object retrieval and generation + @classmethod def from_table_row(cls: type[BaseModelInstance], # pylint: disable=unused-argument @@ -326,7 +339,7 @@ class BaseModel(Generic[BaseModelId]): """ obj = None if id_ is not None: - obj = cls.get_cached(id_) + obj = cls._get_cached(id_) if not obj: for row in db_conn.row_where(cls.table_name, 'id', id_): obj = cls.from_table_row(db_conn, row) @@ -404,6 +417,8 @@ class BaseModel(Generic[BaseModelId]): return filtered return items + # database writing + def save(self, db_conn: DatabaseConnection) -> None: """Write self to DB and cache and ensure .id_. @@ -417,10 +432,9 @@ class BaseModel(Generic[BaseModelId]): """ values = tuple([self.id_] + [getattr(self, key) for key in self.to_save]) - q_marks = DatabaseConnection.q_marks_from_values(values) table_name = self.table_name - cursor = db_conn.exec(f'REPLACE INTO {table_name} VALUES {q_marks}', - values) + cursor = db_conn.exec_on_vals(f'REPLACE INTO {table_name} VALUES', + values) if not isinstance(self.id_, str): self.id_ = cursor.lastrowid # type: ignore[assignment] self.cache() @@ -434,7 +448,9 @@ class BaseModel(Generic[BaseModelId]): def remove(self, db_conn: DatabaseConnection) -> None: """Remove from DB and cache, including dependencies.""" - if self.id_ is None or self.__class__.get_cached(self.id_) is None: + # pylint: disable=protected-access + # (since we remain within class) + if self.id_ is None or self.__class__._get_cached(self.id_) is None: raise HandledException('cannot remove unsaved item') for attr_name in self.to_save_versioned: getattr(self, attr_name).remove(db_conn)