Python数据库dml操作之Oracle

1.cx_Oracle概述
cx_Oracle是一个Python 扩展模块，通过使用所有数据库访问模块通用的数据库 API来实现 Oracle 数据库的查询和更新。为使用一些专为 Oracle 设计的特性，还加入了多个通用数据库 API 的扩展。cx_Oracle 的开发历时多年，涵盖了大多数需要在 Python 中访问 Oracle 的客户的需求。
安装cx_Oracle使用pip命令： pip install cx_Oracle

2.连接oracle数据库

方法一：
cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')
cx_Oracle.connect(连接)('用户名','密码','回环地址：端口号/orcl')
方法二：
cx_Oracle.connect('scott/scott@127.0.0.1:1521/orcl')
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3.ORACLE的查询
简单查询

import cx_Oracle

db_conn = cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')
db_cursor=db_conn.cursor()
sql_cmd='SELECT * FROM students'
db_cursor.execute[执行](sql_cmd)
for row in db_cursor:
　　　　print(row)
db_cursor.close()
db_conn.close()

#带参数查询
db_conn = cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')
db_cursor=db_conn.cursor()
sql_cmd='SELECT * FROM students where ID = :id'
sql_p_id={'id':2}
db_cursor.execute(sql_cmd,sql_p_id)
for row in db_cursor:
　　　　print(row)
db_cursor.close()
db_conn.close()
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#获取单行可以使用fetchone函数;
#获取多行记录，可以使用fetchall函数

import cx_Oracle
db_conn = cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')
db_cursor=db_conn.cursor()
sql_cmd='SELECT * FROM students'
db_cursor.execute(sql_cmd)
print(db_cursor.fetchone())
db_cursor.close()
db_conn.close()
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4.ORACLE的DML

import cx_Oracle
from datetime import datetime
db_conn = cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')

db_cursor=db_conn.cursor()
sql_cmd = 'INSERT INTO students(id, name, age,birth) VALUES(:id, :name, :age,:birth)'
db_cursor.execute(sql_cmd,(11,'王五2',12,datetime(2017,9,1,12,40,12)))
db_cursor.execute(sql_cmd,(22,'赵六',12,datetime(2017,9,1,12,40,12)))
db_conn.commit()
db_cursor.close()
db_conn.close()

import cx_Oracle
from datetime import datetime
db_conn = cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')

db_cursor=db_conn.cursor()
sql_cmd = 'INSERT INTO students(id, name, age,birth) VALUES(:id, :name, :age,:birth)'
db_cursor.executemany(sql_cmd, [(15, '王五2', 12, datetime(2017, 9, 1, 12, 40, 12)),(16, '赵六', 12, datetime(2017, 9, 1, 12, 40, 12))])
db_conn.commit()
db_cursor.close()
db_conn.close()
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5.调用存储过程和函数
存储过程代码：

CREATE OR REPLACE PROCEDURE P_DEMO(V1 IN VARCHAR2, V2 OUT VARCHAR2) IS
BEGIN
V2 := V1;
END;
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#Python代码：
import cx_Oracle
db_conn = cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')
db_cursor=db_conn.cursor()
str='abdd'
msg =db_cursor.var(cx_Oracle.STRING)
db_cursor.callproc('p_demo',[str,msg])
db_conn.commit()
print(msg)
print(msg.getvalue())
db_cursor.close()
db_conn.close()
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--函数代码：
CREATE OR REPLACE function F_DEMO(V1 VARCHAR2,V2 VARCHAR2) RETURN VARCHAR2
IS
BEGIN
RETURN V1 || v2;
END;
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#Python代码：
import cx_Oracle
db_conn = cx_Oracle.connect('scott', 'scott', '127.0.0.1:1521/orcl')
db_cursor=db_conn.cursor()
str=db_cursor.callfunc('f_demo',cx_Oracle.STRING,['abc','ddd'])
print(str)
db_conn.commit()
db_cursor.close()
db_conn.close()
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