使用psycopg插入的问题

问题描述

我正在使用Pytables模块从.mat文件读取数据.读取数据后，我想使用psycopg将此数据插入数据库.这是一个示例代码段:

I am reading data from a .mat file using the Pytables module. After reading the data, I want to insert this data into the database using psycopg.Here is a sample code piece:

file = tables.openFile(matFile)
x = 0
#populate the matData list
for var in dest:
   data = file.getNode('/' + var)[:]
   matData.append(data) 
   x = x+1 
#insert into db
for i in range(0,x):
   cur.execute("""INSERT INTO \"%s\" (%s) VALUES (%s)""" % tableName,dest[i],matData[i]) )

我遇到以下错误:

Traceback (most recent call last):
  File "./loadDBFromMAT.py", line 111, in <module>
    readInputFileAndLoad(args.matFileName,args.tableName)
  File "./loadDBFromMAT.py", line 77, in readInputFileAndLoad
    cur.execute("INSERT INTO \"%s\" (%s) VALUES (%s)" % (tableName,dest[i],matData[i]) )
psycopg2.ProgrammingError: syntax error at or near "["
LINE 1: INSERT INTO "DUMMY1km" (data) VALUES ([[-3000 -3000 -3000 .....

如果有人可以提出解决办法，那就太好了.谢谢！

It would be great if anyone can suggest a workaround for this.Thanks!

推荐答案

INSERT语句的语法无效.您提到的for循环中有问题.

The INSERT statement has invalid syntax. There something wrong inside the for loop you mention.

一个有效的语句可能看起来像这样-假设您的列的类型为integer[].

A valid statement could look like this - assuming your column is of type integer[].

INSERT INTO "DUMMY1km"(data) VALUES ('{-3000, -3000}'::int[])

或

INSERT INTO "DUMMY1km"(data) VALUES (ARRAY[-3000, -3000])  -- note the "ARRAY"

或用于二维数组(看起来与错误味精类似):

or for a 2-dimensional array (looks a bit like that in the error msg.):

INSERT INTO "DUMMY1km"(data) VALUES ('{{-3000, -3000}, {-3000, -3000}}'::int[])

或

INSERT INTO "DUMMY1km"(data) VALUES (ARRAY[[-3000, -3000],[-3000, -3000]])

有关手册中数组值输入的更多信息

More on array value input in the manual.

matData [i]必须包含ARRAY[-3000, -3000]或其他列出的有效语法变体之一，而不是[[-3000 -3000 -3000 ...，后者对整数数组无效.

matData[i] needs to contain ARRAY[-3000, -3000] or one of the other listed variants of valid syntax instead of [[-3000 -3000 -3000 ... which isn't valid for an integer array.

Psychopg自动将 PostgreSQL数组转换为 Python列表.构建INSERT时，需要将列表转换回数组.我引用了此处:

Psychopg automatically converts a PostgreSQL array into a Python list. When building the INSERT, you need to convert the list back to an array. I quote from here:

Python lists are converted into PostgreSQL ARRAYs:

>>> cur.mogrify("SELECT %s;", ([10, 20, 30], ))
'SELECT ARRAY[10, 20, 30];'

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