Question

我使用python在postgreqsl中创建了一个表，并希望用包含不同数据类型的随机数据集填充它。但是我收到错误＆＃39; 并非在字符串格式化期间转换了所有参数＆＃39;。任何人都知道我做错了什么。我已阅读其他帖子，但我无法找到解决方案。

创建表

def create_tables():
""" create table in the PostgreSQL database"""
commands = (
    """
    Create TABLE flight_observations(
            time TIMESTAMP,
            numDayofweek INTEGER,
            numHour INTEGER,
            ac_type TEXT,
            adep TEXT,
            ades TEXT,
            curr_sect TEXT,
            lon_t FLOAT(6),
            lat_t FLOAT(6),
            vg_t INTEGER,
            hdot_t FLOAT8,
            bearing FLOAT8,
            WCA FLOAT8,
            ws FLOAT8,
            wd FLOAT8,
            temp INTEGER
    )
    """)
conn = None
try:
    # connection string
    conn_string = "host='localhost' dbname='postgres' user='postgres' password='xxxx'"
    # print connection string to connect
    print "Connecting to database\n ->%s" % (conn_string)
    # read the connection parameters
    params = Config()
    # connect to the PostgreSQL server
    conn = psycopg2.connect(conn_string)
    cur = conn.cursor()
    # create table one by one

    cur.execute(commands)
    # close communication with the PostgreSQL database server
    cur.close()
    # commit the changes
    conn.commit()
except (Exception, psycopg2.DatabaseError) as error:
    print(error)
finally:
    if conn is not None:
        conn.close()

数据

flight_obs = ['2016-07-01 16:42:21', 'A319', 'EDDB', 'EGKK', 'EDYYSOLX', 11.071111, 52.366389, 206.5938752827827, 5.55, 268.9576458923286, 5.238123301016344, 29.257257205897805, 234.0554644610864, 221.8523282183259]

填表

def insert_flight_list(flight_obs):
sql = "INSERT INTO flight_observations(time, ac_type, adep, ades, curr_sect, lon_t, lat_t, vg_t, hdot_t, bearing, wca, ws, wd, temp) VALUES ( %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)"
conn = None
try:
    # connection string
    conn_string = "host='localhost' dbname='postgres' user='postgres' password='xxxx'"
    # print connection string to connect
    print "Connecting to database\n ->%s" % (conn_string)
    # read database configuration
    params = Config()
    # connect to the PostgreSQL database
    conn = psycopg2.connect(conn_string)
    # create a new cursor
    cur = conn.cursor()
    # execute the INSERT statement
    cur.executemany(sql, flight_obs)
    conn.commit()
    cur.close()
except (Exception, psycopg2.DatabaseError) as error:
    print(error)
finally:
    if conn is not None:
        conn.close()

insert_flight_list(flight_obs)

不确定为什么try语句没有在这篇文章中缩进。它们在python代码中缩进

Answer 1

我认为问题出在cur.executemany(sql, flight_obs)。文档说：

executemany（sql，vars_list）

对序列vars_list中的所有参数元组或映射执行数据库操作（查询或命令）。

所以它实际上相当于：

for i in flight_obs:
    cur.execute(sql, i)

由于flight_obs是一个字符串列表，而不是元组/映射，因此您最终得到的结果如下：

cur.execute(sql, '2016-07-01 16:42:21')
cur.execute(sql, 'A319')
cur.execute(sql, 'EDDB')

简单修复 - 只需将cur.executemany替换为cur.execute，它就可以正常工作。

Answer 2

转动你的＆＃34; flight_obs＆＃34;在将它传递给executemany（）

之前进入元组

cur.executemany(sql, tuple(flight_obs))

顺便说一下，你想要＆＃34; exeutemany＆＃34;或者只是＆＃34;执行＆＃34;？

使用python将行插入Postgresql

2 个答案: