背景：
我对SqlAlchemy很陌生，对于我应该如何选择东西似乎相当困惑。
我的mysql数据库中有一个名为genes的表，其中有gene_id、gene_description和gene_symbol
我想做的是：
我只想做一个简单的选择查询：
Select * from Genes
但我似乎对我们如何实现这一目标感到困惑
以下是我所做的：
import sqlalchemy
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.automap import automap_base
import csv
import pandas as pd
engine = sqlalchemy.create_engine('mysql://root:toor@localhost') # connect to server
metadata = sqlalchemy.MetaData(bind=engine)
engine.execute("USE TestDB")
genes = sqlalchemy.table('Genes')
s = sqlalchemy.select([genes])
engine.execute(s)
问题是：
ProgrammingError: (_mysql_exceptions.ProgrammingError) (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM `Genes`' at line 2") [SQL: u'SELECT \nFROM `Genes`']
还有一种“智能感知”，我可以做一些事情，比如gene_table=engine.gene。如果我没有错的话，有一种方法可以通过映射来实现这一点，但是它对我来说不起作用
编辑：
这可能有助于：
How to automatically reflect database to sqlalchemy declarative?
最佳答案
因此，我们可以使用反射，而不必显式地创建类，但是如果我们需要速度，我们可以使用如下所述的sqlautocode来创建它们：
Reverse engineer SQLAlchemy declarative class definition from existing MySQL database?
另外，mysql数据库也有一个问题，它会给出如下错误：（取自bitbucket:https://bitbucket.org/zzzeek/sqlalchemy/issues/1909/reflection-issue-with-mysql-url-with-no）
SNIP...
File "/opt/buildout-eggs/SQLAlchemy-0.6.4-py2.5.egg/sqlalchemy/schema.py", line 1927, in __init__
self.reflect()
File "/opt/buildout-eggs/SQLAlchemy-0.6.4-py2.5.egg/sqlalchemy/schema.py", line 2037, in reflect
connection=conn))
File "/opt/buildout-eggs/SQLAlchemy-0.6.4-py2.5.egg/sqlalchemy/engine/base.py", line 1852, in table_names
return self.dialect.get_table_names(conn, schema)
File "<string>", line 1, in <lambda>
File "/opt/buildout-eggs/SQLAlchemy-0.6.4-py2.5.egg/sqlalchemy/engine/reflection.py", line 32, in cache
return fn(self, con, *args, **kw)
File "/opt/buildout-eggs/SQLAlchemy-0.6.4-py2.5.egg/sqlalchemy/dialects/mysql/base.py", line 1791, in get_table_names
self.identifier_preparer.quote_identifier(current_schema))
File "/opt/buildout-eggs/SQLAlchemy-0.6.4-py2.5.egg/sqlalchemy/sql/compiler.py", line 1517, in quote_identifier
return self.initial_quote + self._escape_identifier(value) + self.final_quote
File "/opt/buildout-eggs/SQLAlchemy-0.6.4-py2.5.egg/sqlalchemy/dialects/mysql/mysqldb.py", line 77, in _escape_identifier
value = value.replace(self.escape_quote, self.escape_to_quote)
AttributeError: 'NoneType' object has no attribute 'replace'
这可以通过添加数据库名称（您正在使用的数据库名称）来解决，如下所示：
engine = create_engine('mysql+mysqldb://USER_NAME:PASSWORD@127.0.0.1/DATABASE_NAME', pool_recycle=3600) # connect to server
我用这个连接正确：
http://docs.sqlalchemy.org/en/latest/orm/extensions/automap.html
而这个：
http://docs.sqlalchemy.org/en/latest/core/engines.html
这也可能有助于：
How to automatically reflect database to sqlalchemy declarative?
我的代码最终如下所示：
from sqlalchemy.ext.automap import automap_base
from sqlalchemy.orm import Session
from sqlalchemy import create_engine
Base = automap_base()
# engine, suppose it has two tables 'user' and 'address' set up
engine = create_engine('mysql+mysqldb://root:toor@127.0.0.1/TestDB', pool_recycle=3600) # connect to server
# reflect the tables
Base.prepare(engine, reflect=True)
# mapped classes are now created with names by default
# matching that of the table name.
Genes = Base.classes.Genes
Address = Base.classes.address
#Start Session
session = Session(engine)
#add a row:
session.add(Genes(Gene_Id=1,Gene_Symbol = "GENE_SYMBOL", Gene_Description="GENE_DESCRIPTION"))
session.commit()
q = session.query(Genes).all()
for gene in q:
print "This is the Gene ID {},\n This is the Gene Desc {},\n this is the Gene symbol {}.".format(gene.Gene_Id,gene.Gene_Description, gene.Gene_Symbol )