使用python在postgresql中执行行

Question

我使用qgis 导入了一个名为tc_bf25的 shapefile ,以下是我在pyscripter中键入的python脚本,

import sys
import psycopg2

conn = psycopg2.connect("dbname = 'routing_template' user = 'postgres' host = 'localhost' password = '****'")
cur = conn.cursor()

query = """
    ALTER TABLE tc_bf25 ADD COLUMN source integer;
    ALTER TABLE tc_bf25 ADD COLUMN target integer;
    SELECT assign_vertex_id('tc_bf25', 0.0001, 'the_geom', 'gid')
;"""
cur.execute(query)

query = """
    CREATE OR REPLACE VIEW tc_bf25_ext AS
    SELECT *, startpoint(the_geom), endpoint(the_geom)
    FROM tc_bf25
;"""
cur.execute(query)

query = """
    CREATE TABLE node1 AS
    SELECT row_number() OVER (ORDER BY foo.p)::integer AS id,
          foo.p AS the_geom
    FROM (
      SELECT DISTINCT tc_bf25_ext.startpoint AS p FROM tc_bf25_ext
      UNION
      SELECT DISTINCT tc_bf25_ext.endpoint AS p FROM tc_bf25_ext
    ) foo
    GROUP BY foo.p
;"""
cur.execute(query)

query = """
    CREATE TABLE network1 AS
    SELECT a.*, b.id as start_id, c.id as end_id
    FROM tc_bf25_ext AS a
      JOIN node AS b ON a.startpoint = b.the_geom
      JOIN node AS c ON a.endpoint = c.the_geom
;"""
cur.execute(query)

query = """
    ALTER TABLE network1 ADD COLUMN shape_leng double precision;
    UPDATE network1 SET shape_leng = length(the_geom)
;"""
cur.execute(query)

我在第二个cur.execute(查询)收到错误,

但是我去pgAdmin检查结果,即使没有发生错误,第一个cur.execute(查询)也没有在我的表中添加新列.

我犯了什么错误？如何解决？

我正在使用Windows 8.1 x64下的postgresql 8.4,python 2.7.6.

Answer 1

使用psycopg2时,默认情况下autocommit设置为False.前两个语句都引用表tc_bf25,但第一个语句对表进行了未提交的更改.因此,请尝试在语句之间运行conn.commit()以查看是否可以解决问题