1.數據庫連接

# 創建連接
def create_conn():
    import pymysql
    conn = pymysql.connect(
        host=‘localhost‘,
        port=3306,
        user=‘root‘,
        password=‘root‘,
        database=‘py‘,
        charset=‘utf8‘
    )
    # 得到一個可以執行SQL語句並且將結果作為字典返回的遊標
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
    
 
return conn, cursor

# 關閉連接
def close_conn(conn, cursor):
    # 關閉光標對象
    cursor.close()
    # 關閉數據庫連接
    conn.close()

2.增

# 單條插入數據
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)

# 批量添加數據
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.刪

# 刪除數據
def DeleteOneDB(sql, data):
    conn, cursor = create_conn()
    print(sql)
    cursor.execute(sql, data)
    conn.commit()
    close_conn(conn, cursor)

# 定義將要執行的SQL語句
sql = "delete from user333 where name=%s;"
data = [("apollo11")]
DeleteOneDB(sql, data)

4.改

# 更改數據
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

# 查詢數據
def SelectDB(sql, action, limit=None):
    conn, cursor = create_conn()
    cursor.execute(sql)
    if action == ‘fetchone‘:
        ret = cursor.fetchone()  # 取一條
    elif action == ‘fetchmany‘ and limit != None:
        ret = cursor.fetchmany(limit)  # 取三條
    else:
        ret = cursor.fetchall()  # 取全部
    for item in ret:
        print(item)
    close_conn(conn, cursor)


# 執行查詢的sql語句
sql = "select name,age from user333;"
# action可選值:fetchone,fetchmany,fetchall
# fetchmany必須提供limit參數
action = ‘fetchmany‘
# 取數據庫前3條數據
SelectDB(sql, action, 3)
# fetchall取所有數據
SelectDB(sql, action)
# fetchone取一條數據
SelectDB(sql, action)

6.創建表SQL

create table userinfo(
  id int auto_increment primary key ,
  name varchar(32) not null unique ,
  age int(2)
)engine =innodb default charset = utf8;
#註意：charset=‘utf8‘ 不能寫成utf-8

pymysql連接數據庫,實現數據庫增刪改查