1.数据库连接
# 创建连接 def create_conn(): import pymysql conn = pymysql.connect( host='localhost', port=3306, user='root', password='root', database='py', charset='utf8' ) # 得到一个可以执行SQL语句并且将结果作为字典返回的游标 cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) return conn, cursor
# 关闭连接 def close_conn(conn, cursor): # 关闭光标对象 cursor.close() # 关闭数据库连接 conn.close()
2.增
# 单条插入数据 def InsertOneDB(sql, data): conn, cursor = create_conn() cursor.executemany(sql, data) conn.commit() close_conn(conn, cursor) sqlInsertOneDB = "insert into user444 (name,age) values (%s,%s);" data = [('john', 26)] InsertOneDB(sqlInsertOneDB, data)
# 批量添加数据 def InsertManyDB(sql, data): conn, cursor = create_conn() cursor.executemany(sql, data) conn.commit() close_conn(conn, cursor) data = [ ('apollo', '28'), ('jack', '21'), ('merry', '29') ] sql = 'insert into user444(name,age) values(%s,%s);' InsertManyDB(sql, data)
3.删
# 删除数据 def DeleteOneDB(sql, data): conn, cursor = create_conn() print(sql) cursor.execute(sql, data) conn.commit() close_conn(conn, cursor) # 定义将要执行的SQL语句 sql = "delete from user333 where name=%s;" data = [("apollo11")] DeleteOneDB(sql, data)
4.改
# 更改数据 def UpdataOneDB(sql, data): conn, cursor = create_conn() print(sql) cursor.execute(sql, data) conn.commit() close_conn(conn, cursor) sql = "update user333 set name=%s where name=%s;" data = ['Lily', 'jack11'] UpdataOneDB(sql, data)
5.查
# 查询数据 def SelectDB(sql, action, limit=None): conn, cursor = create_conn() cursor.execute(sql) if action == 'fetchone': ret = cursor.fetchone() # 取一条 elif action == 'fetchmany' and limit != None: ret = cursor.fetchmany(limit) # 取三条 else: ret = cursor.fetchall() # 取全部 for item in ret: print(item) close_conn(conn, cursor) # 执行查询的sql语句 sql = "select name,age from user333;" # action可选值:fetchone,fetchmany,fetchall # fetchmany必须提供limit参数 action = 'fetchmany' # 取数据库前3条数据 SelectDB(sql, action, 3) # fetchall取所有数据 SelectDB(sql, action) # fetchone取一条数据 SelectDB(sql, action)
6.创建表SQL
create table userinfo( id int auto_increment primary key , name varchar(32) not null unique , age int(2) )engine =innodb default charset = utf8; #注意：charset='utf8' 不能写成utf-8