sql-server connection python django

1. Preparations

python3.6 connections necessary to introduce pymssql sqlserver database module

pymssql official: https://pypi.org/project/pymssql/

There is no need to install it:

pip install:

pip install pymssql

2. Connect database

First you have to define the target database: 'server name', "account name", "password", "database name"

Because these parameters are necessary

Here use the local database for testing:

Here is the link statement:

import pymssql # introduced pymssql module


def conn():
    connect = pymssql.connect ( '(local)', 'sa', '**********', 'test') # server name, account, password, database name
    if connect:
        print ( "connection success!")
    return connect


if __name__ == '__main__':
    conn = conn()

operation result:

connection succeeded!

Process finished with exit code 0

3. CRUD (CRUD)

Create a new database table:

import pymssql

connect = pymssql.connect ( '(local)', 'sa', 'password1633', 'test') # establish a connection
if connect:
    print ( "connection success!")
    
cursor = connect.cursor () # create a cursor object, python in the sql statement must be performed by a cursor
cursor.execute("create table C_test02(id varchar(20))")   #执行sql语句
connect.commit()  #提交
cursor.close()   #关闭游标
connect.close()  #关闭连接

注意当执行更改数据库表的操作时,执行完sql后别忘记加一句commit().

close()是必须的,否则python程序会一至占用这个数据库.

增加(Create):

import pymssql

connect = pymssql.connect('(local)', 'sa', 'password1633', 'test')  #建立连接
if connect:
    print("连接成功!")
    
cursor = connect.cursor()   #创建一个游标对象,python里的sql语句都要通过cursor来执行
sql = "insert into C_test (id, name, sex)values(1002, '张si', '女')"
cursor.execute(sql)   #执行sql语句
connect.commit()  #提交
cursor.close()   
connect.close()

运行结果:

查询(Retrieve):

import pymssql

connect = pymssql.connect('(local)', 'sa', 'password1633', 'test')  #建立连接
if connect:
    print("连接成功!")
    
cursor = connect.cursor()   #创建一个游标对象,python里的sql语句都要通过cursor来执行
sql = "select name, sex from C_test"
cursor.execute(sql)   #执行sql语句
row = cursor.fetchone()  #读取查询结果,
while row:              #循环读取所有结果
    print("Name=%s, Sex=%s" % (row[0],row[1]))   #输出结果
    row = cursor.fetchone()

cursor.close()   
connect.close()

运行结果:

Update (Update) and delete (Delete) operations are similar. Rewritten sql statement on the line.

With use of a cursor and stored procedures

Pymssql database connections manner and using substantially the same sqlite:

Use connectcreate a connection object
connect.cursorCreate a cursor object, execute SQL statements basically carried out on the cursor
cursor.executeXXXMethod executes SQL statements, cursor.fetchXXXget the query results, etc.
Call the closemethod Closes the cursor cursorand database connections

import pymssql

# server 数据库服务器名称或IP # user 用户名 # password 密码 # database 数据库名称 conn = pymssql.connect(server, user, password, database) cursor = conn.cursor() # 新建、插入操作 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.')]) # 如果没有指定autocommit属性为True的话就需要调用commit()方法 conn.commit() # 查询操作 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() # 也可以使用for循环来迭代查询结果 # for row in cursor: # print("ID=%d, Name=%s" % (row[0], row[1])) # 关闭连接 conn.close()

Note: Examples of parameters used in a query operation %sinstead '%s', if the parameter value is a string, it will automatically single quotes when executing the statement

Note the use of the cursor

A connection only one cursor query is active, as follows:

c1 = conn.cursor()
c1.execute('SELECT * FROM persons') c2 = conn.cursor() c2.execute('SELECT * FROM persons WHERE salesrep=%s', 'John Doe') print( "all persons" ) print( c1.fetchall() ) # 显示出的是c2游标查询出来的结果 print( "John Doe" ) print( c2.fetchall() ) # 不会有任何结果

To avoid this problem you can use the following two ways:

Create multiple connections to ensure that multiple queries can be executed in parallel on different connection cursor
Use fetchalllower again after the execution method to get the cursor to the results of a query, as follows:

c1.execute('SELECT ...') c1_list = c1.fetchall() c2.execute('SELECT ...') c2_list = c2.fetchall()

Cursor behavior dictionary variable return

Each row of the query results obtained above example, the cursor tuple type,
can specify when you create a cursor as_dictto the cursor variable parameter returns the dictionary,
the dictionary key is the data table column names

conn = pymssql.connect(server, user, password, database)
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()

Use `with`statement (context manager)

By using withstatement to display the call omitted closeclose the connection method and cursors

with pymssql.connect(server, user, password, database) 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']))

Call a stored procedure

above 2.0.0 version pymssql can cursor.callprocto call a stored procedure method

with pymssql.connect(server, user, password, database) as conn: with conn.cursor(as_dict=True) as cursor: # 创建存储过程 cursor.execute(""" CREATE PROCEDURE FindPerson @name VARCHAR(100) AS BEGIN SELECT * FROM persons WHERE name = @name END """) # 调用存储过程 cursor.callproc('FindPerson', ('Jane Doe',)) for row in cursor: print("ID=%d, Name=%s" % (row['id'], row['name']))