mysql / connector python查詢在mysql中有效，但在python中不起作用

Question

我已經看到以下兩個答案：

• python-mysql查詢不起作用
• SQL查詢可在控制台中使用，但不適用於python

兩種解決方案都不適合我。 我正在運行下面的代碼，該代碼每次都完整無誤地完成，但根本不會修改mysql表Compounds ，並且我已驗證輸入文件的格式與我的mysql表的格式完全匹配，並且正確定界，不能為空。

import os, sys
import mysql.connector
from mysql.connector import errorcode
from mysql.connector.constants import ClientFlag

TABLE_NAME = "Compounds"
fullDataFile  = "data/compounds/parsed/fullData.csv"
cnx = mysql.connector.connect(user='kharland', passwd='password', db='mydb', client_flags=[ClientFlag.LOCAL_FILES])
cursor = cnx.cursor()
print "loading data file: %s/%s" % (os.getcwd(), fullDataFile)
try:
  cursor.execute = (
    "LOAD DATA LOCAL INFILE '%s/%s'"
    " REPLACE"
    " INTO TABLE `%s`"
    " FIELDS TERMINATED BY '^'"
    " LINES TERMINATED BY '\n'"
    " (PUBCHEM_COMPOUND_CID,"
    " PUBCHEM_COMPOUND_CANONICALIZED,"
    " PUBCHEM_CACTVS_COMPLEXITY,"
    " PUBCHEM_CACTVS_HBOND_ACCEPTOR,"
    " PUBCHEM_CACTVS_HBOND_DONOR,"
    " PUBCHEM_CACTVS_ROTATABLE_BOND,"
    " PUBCHEM_CACTVS_SUBSKEYS,"
    " PUBCHEM_IUPAC_INCHI,"
    " PUBCHEM_IUPAC_INCHIKEY,"
    " PUBCHEM_EXACT_MASS,"
    " PUBCHEM_MOLECULAR_FORMULA,"
    " PUBCHEM_MOLECULAR_WEIGHT,"
    " PUBCHEM_OPENEYE_CAN_SMILES,"
    " PUBCHEM_OPENEYE_ISO_SMILES,"
    " PUBCHEM_CACTVS_TPSA,"
    " PUBCHEM_MONOISOTOPIC_WEIGHT,"
    " PUBCHEM_TOTAL_CHARGE,"
    " PUBCHEM_HEAVY_ATOM_COUNT,"
    " PUBCHEM_ATOM_DEF_STEREO_COUNT,"
    " PUBCHEM_ATOM_UDEF_STEREO_COUNT,"  
    " PUBCHEM_BOND_DEF_STEREO_COUNT,"
    " PUBCHEM_BOND_UDEF_STEREO_COUNT,"
    " PUBCHEM_ISOTOPIC_ATOM_COUNT,"
    " PUBCHEM_COMPONENT_COUNT,"
    " PUBCHEM_CACTVS_TAUTO_COUNT);"  %
    (os.getcwd(), fullDataFile, TABLE_NAME))
  cnx.commit()
except mysql.connector.Error as e:
  sys.stderr.write("x Failed loading data: {}\n".format(e))

但是，如果我將此查詢打印到終端，然后在mysql中運行，則工作正常。 mysql lib是否可能無法運行實際查詢是有原因，還是我錯過了一些函數調用？

Answer 1

MySQL不接受標識符的綁定占位符。 在這種情況下，表的名稱。 那必須是SQL文本的一部分。 您只能使用綁定占位符提供值 。

你可以這樣做：

SELECT t.id FROM mytable t WHERE t.foo = :val
                                         ^^^^

但這是無效的 ：

SELECT t.id FROM :mytable t WHERE t.foo = 'bar'
                 ^^^^^^^^ 

您可以在之前的步驟中執行sprintf -type操作，以生成包含實際表名的SQL文本（字符串），然后將該SQL文本（字符串）提交給MySQL。

到達該cursor.execute ，需要SQL文本將表名作為字符串的一部分包括在內 。 （文件名也可能必須指定為文字，並且不能用作占位符，但是我不確定。我確定的是表名。）

---

作為測試，請嘗試對表名“ Compounds”進行硬編碼，然后將文件名硬編碼為SQL文本...

cursor.execute = (
    "LOAD DATA LOCAL INFILE '/opt/data/compounds/parsed/fullData.csv'"
    " REPLACE"
    " INTO TABLE `Compounds`"