143 lines
3.7 KiB
Python
143 lines
3.7 KiB
Python
import enum
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import sqlite3
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class DatabaseOrder(enum.Enum):
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DEFAULT = 0
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ASC = 1
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DESC = 2
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class DatabaseTable():
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pass
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class DatabaseTableCursor():
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__slots__ = 'cr', 'table',
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def __init__(self, table, cr):
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self.cr = cr
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self.table = table
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def __getattr__(self, name):
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return getattr(self.cr, name)
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def __map__(self, row):
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fn = getattr(self.table, '__from_row__', None)
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if fn is not None:
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return fn(row)
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obj = self.table()
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for name in self.table.columns:
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try:
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setattr(obj, name, row[name])
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except IndexError:
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setattr(obj, name, None)
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return obj
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def fetchone(self):
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row = self.cr.fetchone()
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return self.__map__(row) if row is not None else None
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def fetchall(self):
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return map(self.__map__, self.cr.fetchall())
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def each(self):
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while True:
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obj = self.fetchone()
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if obj is None:
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break
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yield obj
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class Database():
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__slots__ = 'db',
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def __init__(self, db):
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self.db = db
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def __getattr__(self, name):
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return getattr(self.db, name)
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@staticmethod
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def connect(path):
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db = sqlite3.connect(path)
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db.row_factory = sqlite3.Row
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return Database(db)
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def add(self, obj):
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table = type(obj)
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sql = f"insert into {table.name} ("
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sql += ", ".join([c for c in table.columns if c != table.key])
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sql += ') values ('
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sql += ", ".join(['?' for c in table.columns if c != table.key])
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sql += ')'
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fn = getattr(obj, '__values__', None)
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if fn is not None:
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values = fn()
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else:
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values = list()
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for column in table.columns:
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if column != table.key:
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values.append(getattr(obj, column))
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self.db.execute(sql, values)
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def query(self, table, values=dict(), order_by=list()):
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sql = f"select * from {table.name}"
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if len(values) > 0:
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sql += " where "
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sql += " and ".join([f"{table.name}.{k} = ?" for k in values])
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if len(order_by) > 0:
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sql += " order by"
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first = True
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for column, order in order_by:
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if first:
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first = False
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else:
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sql += ", "
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if order is None or order is DatabaseOrder.DEFAULT:
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sql += f" {column}"
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elif order is DatabaseOrder.ASC:
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sql += f" {column} asc"
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elif order is DatabaseOrder.DESC:
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sql += f" {column} desc"
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cr = DatabaseTableCursor(table, self.db.cursor())
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cr.execute(sql, list(values.values()))
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return cr
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def get(self, table, values: dict=dict()):
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return self.query(table, values).fetchone()
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def _call(self, table, fn: str, column: str, values: dict=dict()) -> int:
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sql = f"select {fn}({column}) as ret from {table.name}"
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if len(values) > 0:
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sql += " where "
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sql += " and ".join([f"{k} = ?" for k in values])
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row = self.db.execute(sql, list(values.values())).fetchone()
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return row[0] if row is not None else None
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def min(self, table, column: str, values: dict=dict()) -> int:
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return self._call(table, 'min', column, values)
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def max(self, table, column: str, values: dict=dict()) -> int:
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return self._call(table, 'max', column, values)
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def count(self, table, values: dict=dict()) -> int:
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return self._call(table, 'count', table.key, values)
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