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()