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"""Wrapper around psycopg2.
Database connection provides regular DB-API 2.0 interface.
Connection object methods::
.cursor()
.commit()
.rollback()
.close()
Cursor methods::
.execute(query[, args])
.fetchone()
.fetchall()
Sample usage::
db = self.get_database('somedb')
curs = db.cursor()
# query arguments as array
q = "select * from table where id = %s and name = %s"
curs.execute(q, [1, 'somename'])
# query arguments as dict
q = "select id, name from table where id = %(id)s and name = %(name)s"
curs.execute(q, {'id': 1, 'name': 'somename'})
# loop over resultset
for row in curs.fetchall():
# columns can be asked by index:
id = row[0]
name = row[1]
# and by name:
id = row['id']
name = row['name']
# now commit the transaction
db.commit()
"""
from typing import cast
import psycopg2
import psycopg2.extensions
import psycopg2.extras
from psycopg2 import Error as DBError
from .basetypes import Connection
__all__ = (
'connect_database', 'DBError', 'I_AUTOCOMMIT', 'I_READ_COMMITTED',
'I_REPEATABLE_READ', 'I_SERIALIZABLE',
)
#: Isolation level for db.set_isolation_level()
I_AUTOCOMMIT = psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT
#: Isolation level for db.set_isolation_level()
I_READ_COMMITTED = psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED
#: Isolation level for db.set_isolation_level()
I_REPEATABLE_READ = psycopg2.extensions.ISOLATION_LEVEL_REPEATABLE_READ
#: Isolation level for db.set_isolation_level()
I_SERIALIZABLE = psycopg2.extensions.ISOLATION_LEVEL_SERIALIZABLE
def connect_database(connstr: str) -> Connection:
"""Create a db connection with DictCursor.
"""
db = psycopg2.connect(connstr, cursor_factory=psycopg2.extras.DictCursor)
return cast(Connection, db)
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