Python库之pymssql连接MSSQL数据库并绘制直方图

pymssql是一个Python的数据库接口，工作原理：
使用connect创建连接对象；
connect.cursor创建游标对象，SQL语句的执行在游标上执行；
cursor.execute()方法执行SQL语句，cursor.fetch()方法获取查询结果；
执行connect.commit()；
调用close方法关闭游标cursor和数据库连接；
一个连接一次只能有一个游标的查询处于活跃状态；
可以通过使用with语句来省去显示的调用close方法关闭连接和游标；
pymssql 2.0.0以上的版本可以通过cursor.callproc方法来调用存储过程；
# 数据存放到元组列表中，如果参数为as_dict=True，返回字典；
# with conn.cursor() as cursor: 
# with conn.cursor(as_dict=True) as cursor:  

import pymssql
import matplotlib.pyplot as plt
# import pandas as pd
# import warnings
# warnings.filterwarnings('ignore') #隐藏Pandas警告SQLAlchemy

#创建连接字符串  （sqlserver默认端口为1433）
conn =pymssql.connect(server="localhost",#本地服务器
                         port="1433",#TCP端口
                         user="sa",password="lqxxxx11",
                         database="tsl",
                         charset="utf8"
 
    )
if conn:
   print('连接数据库成功!')#
# 创建游标对象
cursor = conn.cursor()
# 编写SQL查询语句
sql_query = "SELECT changeInto FROM cash123122 where paymentMethod LIKE N'%代发%'" 
cursor.execute(sql_query)
rows=cursor.fetchall()
list2=[]
for row in rows:
    list2.append(row[0])
    print(row[0])

# 绘制第二个直方图
plt.hist(list2, bins=60, alpha=0.5,rwidth=0.7)
plt.xlabel('Value')
plt.ylabel('Frequency')
plt.show()

# 关闭数据库连接
conn.close()

import pymssql

#创建连接字符串  （sqlserver默认端口为1433）
conn =pymssql.connect(server="localhost",#本地服务器
                         port="1433",#TCP端口
                         user="sa",password="lqxxx1",
                         database="tsl",
                         charset="utf8"
 
    )
if conn:
   print('连接数据库成功!')#测试是否连接上
# 创建游标对象
cursor = conn.cursor()

# 执行SQL查询
cursor.execute("SELECT * FROM Employees")

# 获取查询结果
result = cursor.fetchall()

# 遍历结果
for row in result:
    # print(row)
    #print("CustomerId: "+ row[0],"CustomerName: "+ row[1],"Email: "+row[2])
    print("CustomerId: %-6s CustomerName: %-10s Email: %-20s" % (row[0], row[1],row[2]))  
    

# # 插入数据
# insert_query = "INSERT INTO Employees (CustomerId,CustomerName,Email) VALUES (%s, %s, %s)"
# insert_data = ('29110', 'liangzh','[email protected]')
# cursor.execute(insert_query, insert_data)

# 更新数据
# update_query = "UPDATE Employees SET CustomerName = %s WHERE CustomerId = 28910"
# update_data = ('liang', )
# cursor.execute(update_query, update_data)

# 删除数据
# delete_query = "DELETE FROM Employees WHERE CustomerName = %s"
# delete_data = ("liangzh",)
# cursor.execute(delete_query, delete_data)

# 提交事务
conn.commit()

# 关闭游标
cursor.close()

Basic features (strict DB-API compliance) 

from os import getenv
import pymssql

server = getenv("PYMSSQL_TEST_SERVER")
user = getenv("PYMSSQL_TEST_USERNAME")
password = getenv("PYMSSQL_TEST_PASSWORD")

conn = pymssql.connect(server, user, password, "tempdb")
cursor = conn.cursor()
cursor.execute("""
IF OBJECT_ID('persons', 'U') IS NOT NULL
    DROP TABLE persons
CREATE TABLE persons (
    id INT NOT NULL,
    name VARCHAR(100),
    salesrep VARCHAR(100),
    PRIMARY KEY(id)
)
""")
cursor.executemany(
    "INSERT INTO persons VALUES (%d, %s, %s)",
    [(1, 'John Smith', 'John Doe'),
     (2, 'Jane Doe', 'Joe Dog'),
     (3, 'Mike T.', 'Sarah H.')])
# you must call commit() to persist your data if you don't set autocommit to True
conn.commit()

cursor.execute('SELECT * FROM persons WHERE salesrep=%s', 'John Doe')
row = cursor.fetchone()
while row:
    print("ID=%d, Name=%s" % (row[0], row[1]))
    row = cursor.fetchone()

conn.close()

pymssql examples — pymssql 0.1.dev50+g55af2c7.d20231007 documentation

 As of pymssql 2.0.0 stored procedures can be called using the rpc interface of db-lib如果要调用存储过程，则使用Cursor对象的callproc方法

with pymssql.connect(server, user, password, "tempdb") as conn:
    with conn.cursor(as_dict=True) as cursor:
        cursor.execute("""
        CREATE PROCEDURE FindPerson
            @name VARCHAR(100)
        AS BEGIN
            SELECT * FROM persons WHERE name = @name
        END
        """)
        cursor.callproc('FindPerson', ('Jane Doe',))
        # you must call commit() to persist your data if you don't set autocommit to True
        conn.commit()
        for row in cursor:
            print("ID=%d, Name=%s" % (row['id'], row['name']))

 Rows can be fetched as dictionaries instead of tuples. This allows for accessing columns by name instead of index. Note the as_dict argument.如果指定了as_dict为True，则返回结果变为字典类型，这样就能通过列名来访问结果了

conn = pymssql.connect(server, user, password, "tempdb")
cursor = conn.cursor(as_dict=True)

cursor.execute('SELECT * FROM persons WHERE salesrep=%s', 'John Doe')
for row in cursor:
    print("ID=%d, Name=%s" % (row['id'], row['name']))

conn.close()

You can use Python’s with statement with connections and cursors. This frees you from having to explicitly close cursors and connections.可以使用with语句来处理Connection和cursor对象，这样就不需要手动关闭他们了：

with pymssql.connect(server, user, password, "tempdb") as conn:
    with conn.cursor(as_dict=True) as cursor:
        cursor.execute('SELECT * FROM persons WHERE salesrep=%s', 'John Doe')
        for row in cursor:
            print("ID=%d, Name=%s" % (row['id'], row['name']))