I´m new on python and am developing an app with python 2.7, and got this nice code for python 3.x that doesn´t work in my version. I´ve been trying to adapt it for it´s beauty but couldn´t see the issue causing compatibility problem. The message i get is: AttributeError: database instance has no attribute '_db'
in line 9.Please help me solve this issue.
#!/usr/bin/python3
import sqlite3
class database:
def __init__(self, **kwargs):
self.filename = kwargs.get('filename')
self.table = kwargs.get('table', 'test')
def sql_do(self, sql, *params):
self._db.execute(sql, params)
self._db.commit()
def insert(self, row):
self._db.execute('insert into {} (t1, i1) values (?, ?)'.format(self._table), (row['t1'], row['i1']))
self._db.commit()
def retrieve(self, key):
cursor = self._db.execute('select * from {} where t1 = ?'.format(self._table), (key,))
return dict(cursor.fetchone())
def update(self, row):
self._db.execute(
'update {} set i1 = ? where t1 = ?'.format(self._table),
(row['i1'], row['t1']))
self._db.commit()
def delete(self, key):
self._db.execute('delete from {} where t1 = ?'.format(self._table), (key,))
self._db.commit()
def disp_rows(self):
cursor = self._db.execute('select * from {} order by t1'.format(self._table))
for row in cursor:
print(' {}: {}'.format(row['t1'], row['i1']))
def __iter__(self):
cursor = self._db.execute('select * from {} order by t1'.format(self._table))
for row in cursor:
yield dict(row)
@property
def filename(self): return self._filename
@filename.setter
def filename(self, fn):
self._filename = fn
self._db = sqlite3.connect(fn)
self._db.row_factory = sqlite3.Row
@filename.deleter
def filename(self): self.close()
@property
def table(self): return self._table
@table.setter
def table(self, t): self._table = t
@table.deleter
def table(self): self._table = 'test'
def close(self):
self._db.close()
del self._filename
def main():
db = database(filename = 'test.db', table = 'test')
print('Create table test')
#db.sql_do('drop table if exists test')
db.sql_do('create table test ( t1 text, i1 int )')
print('Create rows')
db.insert(dict(t1 = 'one', i1 = 1))
db.insert(dict(t1 = 'two', i1 = 2))
db.insert(dict(t1 = 'three', i1 = 3))
db.insert(dict(t1 = 'four', i1 = 4))
for row in db: print(row)
print('Retrieve rows')
print(db.retrieve('one'), db.retrieve('two'))
print('Update rows')
db.update(dict(t1 = 'one', i1 = 101))
db.update(dict(t1 = 'three', i1 = 103))
for row in db: print(row)
print('Delete rows')
db.delete('one')
db.delete('three')
for row in db: print(row)
if __name__ == "__main__": main()
On Python 2.x you need to declare the class a new-style class by inheriting from object
, because it uses properties. Properties are only supported by new-style classes.
class database(object):
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