Python连接oracle数据库的基本操作

1，数据库连接和关闭

 # 引入cx_Oracle模块
 import cx_Oracle
 ​
 '''
 方法一：用户名、密码和监听分开写
 '''
 db = cx_Oracle.connect('username/password@host/orcl')
 ​
 '''
 方法二：用户名、密码和监听写在一起
 '''
 db = cx_Oracle.connect('username','password','host/orcl')
 ​
 '''
 方法三：配置监听并连接
 '''
 tns = cx_Oracle.makedsn('host',1521,'orcl')
 db = cx_Oracle.connect('username','password',tns)

2，数据库增删改查操作

　    建立cursor并执行SQL语句：查询、更新、插入、删除，执行完成后，关闭游标，关闭数据库连接

　　1，数据库查询操作

 # 导入cx_Oracle模块
 import cx_Oracle as cx
 ​
 # 连接数据库
 db = cx.connect('username/password@host/orcl')
 ​
 # 创建光标
 cur = db.cursor()
 ​
 '''
     无需传递参数
 '''
 sql = '''SELECT * FROM TABLE'''
 ​
 # 执行sql语句
 cur.execute(sql)
 ​
 '''
     需要传递参数
 '''
 ​
 # 字典只有一个键值对
 pm = {'id': 1}
 cur.execute('SELECT * FROM TABLE WHERE ID = :id', pm)
 ​
 # 字典有多个键值对
 pa = {'id': 1, 'name': '卡卡'}
 cur.execute('SELECT * FROM TABLE WHERE ID = :id AND NAME = :name', pa)
 ​
 # 名字参数
 cur.execute('''SELECT * FROM TABLE WHERE ID = :id''', id = 1)
 ​
 cur.execute('''SELECT * FROM TABLE WHERE ID = :id AND NAME = :name''', id = 1, name = '卡卡')
 ​
 # 位置参数,数据为元组，只有一个参数时，需加逗号
 cur.execute('''SELECT * FROM TABLE WHERE ID = :a''', (1,))
 ​
 cur.execute('''SELECT * FROM TABLE WHERE ID = :a AND NAME = :b''', (1, '卡卡'))
 ​
 # cur.Prepare的用法,prepare之后，你再去execute的时候，就不用写上sql语句参数了
 # 传递参数的方式与以上方式相同
 ​
 cur.prepare('''SELECT * FROM TABLE WHERE ID = :id''')
 ​
 # 注意，第一个参数是None
 cur.execute(None, {'id': 1})
 ​
 c_id = 1
 c_name = "卡卡"
 ​
 # %格式化字符串，%s格式化的字符串不带引号，%r格式化的字符串带单引号
 sql = '''SELECT * FROM TABLE WHERE ID = %s''' % c_id
 ​
 sql = '''SELECT * FROM TABLE WHERE ID = %s AND NAME = %r''' % (c_id, c_name)
 ​
 # format格式化字符串
 sql = '''SELECT * FROM TABLE WHERE ID = {} '''.format(c_id)
 ​
 sql = '''SELECT * FROM TABLE WHERE ID = {0} AND NAME = '{1}' '''.format(c_id, c_name)
 ​
 # 执行sql
 cur.execute(sql)
 ​
 '''
     一次性返回所有的结果集(fetchall)
 '''
 rs = cur.fetchall()
 print(rs)
 for r in rs:
     print(r)
 ​
 '''
     一次返回一行(fetchone)
 '''
 while(1):
     rs = cur.fetchone()
     if rs == None:
         break
     print(rs)

 # 关闭光标
 cur.close()
 ​
 # 数据库断开连接
 db.close()

　　2，插入、更新、删除操作后需要提交commit

 # 导入cx_Oracle模块
 import cx_Oracle as cx
 ​
 # 连接数据库
 db = cx.connect('username/password@host/orcl')
 ​
 # 创建光标
 cur = db.cursor()
 ​
 '''
 INSERT
 '''
 sql = 'INSERT INTO TABLE(ID) VALUES(1)'
 ​
 '''
 UPDATE
 '''
 sql = 'UPDATE TABLE  SET ID = 2'
 ​
 '''
 DELETE
 '''
 sql = 'DELETE FROM TABLE  WHERE ID = 2'
 ​
 # 执行sql
 cur.execute(sql)
 ​
 # 关闭光标
 cur.close()
 ​
 # 数据库提交
 db.commit()
 ​
 # 关闭数据库
 db.close()