Python 检索后更新postgresql
您好,我正在使用服务器端游标功能从PostgreSQL检索大型数据集。我需要获取该行(然后对其执行一些操作),然后更新一个布尔列以指示其已被处理。这就是我迄今为止所尝试的:-Python 检索后更新postgresql,python,postgresql,psycopg2,Python,Postgresql,Psycopg2,您好,我正在使用服务器端游标功能从PostgreSQL检索大型数据集。我需要获取该行(然后对其执行一些操作),然后更新一个布尔列以指示其已被处理。这就是我迄今为止所尝试的:- import psycopg2 import psycopg2.extras import sys query = """ select * from exports; """ con = psycopg2.connect("dbname='test' user='postgres' password='*
import psycopg2
import psycopg2.extras
import sys
query = """
select * from exports;
"""
con = psycopg2.connect("dbname='test' user='postgres' password='*****'")
cursor = con.cursor('server_side_cursor', cursor_factory=psycopg2.extras.DictCursor)
cursor.execute(query)
while True:
rows = cursor.fetchmany(5000)
if not rows:
break
row_count = 0
for row in rows:
row_count += 1
print "row: %s %s\n" % (row_count, row['id'])
cursor.execute("UPDATE exports SET (status) = (true), WHERE id = row['id']")
pass
con.close()
但是,我得到了以下错误:-
psycopg2.ProgrammingError: can't call .execute() on named cursors more than once
您需要一个新光标来执行更新查询:
import psycopg2
import psycopg2.extras
import sys
query = """select * from exports;"""
con = psycopg2.connect("dbname='test' user='postgres' password='*****'")
cursor = con.cursor('server_side_cursor', cursor_factory=psycopg2.extras.DictCursor)
cursor.execute(query)
while True:
rows = cursor.fetchmany(5000)
if not rows:
break
row_count = 0
for row in rows:
row_count += 1
print "row: %s %s\n" % (row_count, row['id'])
cursor2 = con.cursor()
cursor2.execute("UPDATE exports SET (status) = (true), WHERE id = row['id']")
cursor2.close()
con.close()