mysql/connector python 查询适用于 mysql 但不适用于 python

Question

我看到了以下两个答案：

python - mysql query not working
SQL query works in console but not in python

这两种解决方案都不适合我。我正在运行ning 下面的代码，它每次都没有任何错误地完成，但根本没有修改 mysql table Compounds，并且我已经验证了输入文件的格式与我的 mysql table 的格式完全匹配，并且分隔正确且不为空。

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，如果我将此查询打印到终端，然后运行它在 mysql 中，那么它就可以正常工作。 mysql lib 是否有可能无法运行实际查询，或者我错过了一些函数调用？

Answer 1

MySQL 不接受标识符的绑定占位符。在本例中，名称为 table。那必须是 SQL 文本的一部分。您只能使用绑定占位符提供值。

你可以这样做：

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

但这无效:

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

您可以先执行 sprintf 类型的操作，生成包含实际 table 名称的 SQL 文本（字符串），然后提交SQL 文本（字符串）到 MySQL.

当您到达 cursor.execute 时，您需要 SQL 文本以包含 table 名称作为字符串的一部分。（也有可能文件名必须指定为文字，不能是占位符，但我不确定。我确定的是 table 名称。）

作为测试，尝试将 table 名称硬编码 "Compounds" 并将文件名硬编码到 SQL 文本中...

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

mysql/connector python 查询适用于 mysql 但不适用于 python

mysql/connector python query works in mysql but not python

python

mysql

mysql-connector