如何使用pymysql通过存储过程将pyodbc mssql查询返回的列表插入mysql

问题描述

我正在使用pyodbc从MSSQL数据库中提取数据，该数据返回列表中的数据集.然后，需要将这些数据传输到MySQL数据库中.我已经在MySQL中编写了以下存储过程.

I am pulling data from a MSSQL db using pyodbc which returns my data set in a list. This data then needs to be transferred into a MySQL db. I have written the following stored procedure in MySQL.

CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_int_pmt`(
    IN pmtamt DECIMAL(16,10),
        IN pmtdt DATETIME,
        IN propmtref VARCHAR(128),
        IN rtdinv_id INT(11)
    )
BEGIN
    INSERT INTO ay_financials.payment
    (
    pmtamt,
        pmtdt,
        propmtref,
        rtdinv_id
    )
VALUES
    (
    pmtamt,
        pmtdt,
        propmtref,
        rtdinv_id
    );

END

如果我一次插入一条记录，则该程序运行正常.因此，现在，我将遍历MSSQL查询中的列表，并为每个记录调用该过程.我正在使用此代码:

The procedure works fine if I am inserting one record at the time. So, for now, I am iterating over the list from my MSSQL query and call the procedure for each record. I am using this code:

cursor = cnxn.cursor()

cursor.execute("""  SELECT *
            FROM [%s].[dbo].[pmt]
            WHERE pmtdt BETWEEN '2018-01-01' AND '2018-12-31'""" %(database))

a = cursor.fetchmany(25)

cnxn.close()

import pymysql

# MySQL configurations
un = 'ssssssss'
pw = '****************'
db = 'ay_fnls'
h = '100.100.100.100'

conn = pymysql.connect(host=h, user=un, password=pw, db=db, cursorclass=pymysql.cursors.DictCursor)

cur = conn.cursor()

for ay in a:
    cur.callproc('sp_int_pmt',(ay.pmtamt,ay.pmtdt,ay.propmtref,ay.rtdinv_id))

conn.commit()

我在生产中遇到的问题是此列表每天将包含10,000-100,000.遍历这些数据似乎不是一种优化的方式来处理此问题.

The problem I will have in production is this list will contain 10,000-100,000 every day. Iterating over that data doesn't seem like an optimized way to handle this.

如何使用MSSQL查询中的完整列表，一次调用MySQL过程并插入所有相关数据?

How can I use the full list from the MSSQL query, call the MySQL procedure one time and insert all the relevant data?

推荐答案

您无法使用书面形式的存储过程来做到这一点.它一次只能插入一行，因此要插入 n 行，您将不得不称其为 n 次.

You can't do that with your stored procedure as written. It will only insert one row at a time, so to insert n rows you would have to call it n times.

据我所知，如果不使用临时表或其他解决方法，您将无法修改存储过程以插入 n 行，因为MySQL不支持存储过程的表值参数

Also, as far as I know you can't modify the stored procedure to insert n rows without using a temporary table or some other workaround because MySQL does not support table-valued parameters to stored procedures.

但是，如果使用常规的INSERT语句和.executemany，则可以一次插入多行. pymysql会将插入物捆绑成一个或多个多行插入物

You can, however, insert multiple rows at once if you use a regular INSERT statement and .executemany. pymysql will bundle the inserts into one or more multi-row inserts

mssql_crsr = mssql_cnxn.cursor()
mssql_stmt = """\
SELECT 1 AS id, N'Alfa' AS txt
UNION ALL
SELECT 2 AS id, N'Bravo' AS txt
UNION ALL
SELECT 3 AS id, N'Charlie' AS txt
"""
mssql_crsr.execute(mssql_stmt)
mssql_rows = []
while True:
    row = mssql_crsr.fetchone()
    if row:
        mssql_rows.append(tuple(row))
    else:
        break

mysql_cnxn = pymysql.connect(host='localhost', port=3307,
                             user='root', password='_whatever_',
                             db='mydb', autocommit=True)
mysql_crsr = mysql_cnxn.cursor()
mysql_stmt = "INSERT INTO stuff (id, txt) VALUES (%s, %s)"
mysql_crsr.executemany(mysql_stmt, mssql_rows)

上面的代码在MySQL general_log中产生以下内容

The above code produces the following in the MySQL general_log

190430 10:00:53     4 Connect   root@localhost on mydb
            4 Query INSERT INTO stuff (id, txt) VALUES (1, 'Alfa'),(2, 'Bravo'),(3, 'Charlie')
            4 Quit

请注意，pymysql无法以相同的方式将调用捆绑到存储过程，因此如果要使用

Note that pymysql cannot bundle calls to a stored procedure in the same way, so if you were to use

mysql_stmt = "CALL stuff_one(%s, %s)"

而不是常规的INSERT，那么general_log将包含

instead of a regular INSERT then the general_log would contain

190430  9:47:10     3 Connect   root@localhost on mydb
            3 Query CALL stuff_one(1, 'Alfa')
            3 Query CALL stuff_one(2, 'Bravo')
            3 Query CALL stuff_one(3, 'Charlie')
            3 Quit

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