对于特定用例 - 我有100个数据库，1个数据库是中央数据库，现在我的应用程序连接到一个中央数据库，根据用户运行的请求产生与100个数据库中的任何一个的连接对它们中的任何一个进行查询。
在这种情况下，确实使用DRCP与我t want the connection to be killed if the user is running the query at the same time I don想要通过在数据库上创建配置文件来控制的数据库打开太多连接相同，这会将活动会话数限制为某个较低的数字，例如5对于使用该特定配置文件（read_only_profile）的特定用户（read_only_user）。
现在我正在使用标准打开每个请求模型的连接。但我m not sure if that是最好的方法。
import cx_Oracle
import logging, time
class Database(object):
'''
Use this method to for DML SQLS :
Inputs - Sql to be executed. Data related to that sql
Returns - The last inserted, updated, deleted ID.
'''
def __init__(self, user, password, host, port, service_name, mode, *args):
#mode should be 0 if not cx_Oracle.SYSDBA
self.user = user
self.password = password
self.host = host
self.port = port
self.user = user
self.service_name = service_name
self.logger = logging.getLogger(__name__)
try:
self.mode = mode
except:
self.mode = 0
self.logger.info(" Mode is not mentioned while creating database object")
self.connection = None
dsn = cx_Oracle.makedsn(self.host, self.port, self.service_name)
self.connect_string = self.user + '/' + self.password + '@' + dsn
try:
self.connection = cx_Oracle.connect(self.connect_string, mode=self.mode,
threaded=True)
self.connection.stmtcachesize = 1000
self.connection.client_identifier = 'my_app'
self.cursor = self.connection.cursor()
self.idVar = self.cursor.var(cx_Oracle.NUMBER)
except cx_Oracle.DatabaseError, exc:
error, = exc
self.logger.exception(
'Exception occured while trying to create database object : %s',
error.message)
raise exc
def query(self, q):
try:
self.cursor.execute(q)
return self.cursor.fetchall()
except cx_Oracle.DatabaseError, exc:
error, = exc
self.logger.info(
"Error occured while trying to run query: %s, error : %s", q,
error.message)
return error.message
def dml_query(self, sql):
try:
self.cursor.execute(sql)
self.connection.commit()
return 1
except Exception as e:
self.logger.exception(e)
return 0
def dml_query_with_data(self, sql, data):
"""
Use this method to for DML SQLS :
Inputs - Sql to be executed. Data related to that sql
Returns - The last inserted, updated, deleted ID.
"""
try:
self.cursor.execute(sql, data)
self.connection.commit()
return 1
except Exception as e:
self.logger.exception(e)
return 0
def update_output(self, clob, job_id, flag):
try:
q = "Select output from my_table where job_id=%d" % job_id
self.cursor.execute(q)
output = self.cursor.fetchall()
#Checking if we already have some output in the clob for that job_id
if output[0][0] is None:
if flag == 1:
self.cursor.execute("""UPDATE my_table
SET OUTPUT = :p_clob
,job_status=:status WHERE job_id = :p_key""",
p_clob=clob, status="COMPLETED", p_key=job_id)
else:
self.cursor.execute("""UPDATE my_table
SET OUTPUT = :p_clob
,job_status=:status WHERE job_id = :p_key""",
p_clob=clob, status="FAILED", p_key=job_id)
else:
self.cursor.execute("""UPDATE my_table
SET OUTPUT = OUTPUT || ',' || :p_clob
WHERE job_id = :p_key""", p_clob=clob, p_key=job_id)
self.connection.commit()
rows_updated = self.cursor.rowcount
return rows_updated
except Exception as e:
self.logger.exception(e)
return 0
def __del__(self):
try:
if self.connection is not None:
self.connection.close()
except Exception as e:
self.logger.exception(
"Exception while trying to close database connection object : %s", e)
'''
if __name__ == '__main__':
db = Database('test', 'test', 'my_host', '1000', 'my_db', 0)
columns = db.query('select * from my-table')
print columns
'''
这是我的数据库类，每当我需要连接到数据库时，我都会创建一个对象。并且 init 和 del 方法负责构造和销毁对象。