使用pyodbc和sqlalchemy连接SQL服务器，不能使用“use database_name;"； [英] Connect to SQL server using pyodbc and sqlalchemy, cannot use "use database_name;"

问题描述

我的代码如下:

import urllib
import sqlalchemy
from sqlalchemy.orm import sessionmaker, scoped_session


def list_dbs():
    sql = """
            use master;
            SELECT name
            FROM   sys.databases;
        """
    try:
        odbc_connect = "DRIVER={SQL Server};Server=localhost;Database=master;port=1433"
        engine = sqlalchemy.create_engine("mssql+pyodbc:///?odbc_connect=%s" % urllib.quote_plus(odbc_connect),
                                          echo=True, connect_args={'autocommit': True})
        SessionFactory = sessionmaker(bind=engine)
        session = scoped_session(SessionFactory)
        result = session.execute(sql)
        for v in result:
            print(v)
    except Exception as e:
        print(e)


list_dbs()

然后出现错误此结果对象不返回行.它已自动关闭."

Then an error "This result object does not return rows. It has been closed automatically."

但后来我删除了use master;"它有效:

But then I remove "use master;" and it works:

因为我有很多数据库，所以我必须使用use databasename".有什么想法吗?

Because I have many databases, I have to use "use databasename." Any ideas?

推荐答案

您正面临 GitHub 上讨论的问题 此处.

You are facing the issue discussed on GitHub here.

就目前而言，您需要单独执行 USE ... ，然后再执行您的查询.示例:

As it stands now, you need to execute the USE ... separately and then execute your queries. Example:

with engine.begin() as conn:
    db_name = conn.execute(text("SELECT DB_NAME()")).fetchone()[0]
    print(f'Current database: {db_name}')  # Current database: myDb
    tables = conn.execute(text("SELECT TOP 3 name FROM sys.tables ORDER BY name")).fetchall()
    print(tables)  # [('MillionRows',), ('myTable',), ('person',)]
    conn.execute(text("USE master"))
    db_name = conn.execute(text("SELECT DB_NAME()")).fetchone()[0]
    print(f'Current database: {db_name}')  # Current database: master
    tables = conn.execute(text("SELECT TOP 3 name FROM sys.tables ORDER BY name")).fetchall()
    print(tables)  # [('MSreplication_options',), ('spt_fallback_db',), ('spt_fallback_dev',)]

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