Python SQLite – 删除表中的数据

在本文中，我们将讨论如何使用 sqlite3 模块从Python程序中删除 SQLite 数据库中表中的数据。在 SQLite 数据库中，我们使用以下语法从表中删除数据：

DELETE FROM table_name [WHERE Clause]

要创建数据库，我们将执行以下代码：

Python3

import sqlite3
 
# Connecting to sqlite
# connection object
connection_obj = sqlite3.connect('geek.db')
 
# cursor object
cursor_obj = connection_obj.cursor()
 
# Drop the GEEK table if already exists.
cursor_obj.execute("DROP TABLE IF EXISTS GEEK")
   
# Creating table
table = """ CREATE TABLE GEEK (
            Email VARCHAR(255) NOT NULL,
            Name CHAR(25) NOT NULL,
            Score INT
        ); """
   
cursor_obj.execute(table)
 
#inserting data into geek table
connection_obj.execute("""INSERT INTO GEEK (Email,Name,Score) VALUES ("geekk1@gmail.com","Geek1",25)""")
connection_obj.execute("""INSERT INTO GEEK (Email,Name,Score) VALUES ("geekk2@gmail.com","Geek2",15)""")
connection_obj.execute("""INSERT INTO GEEK (Email,Name,Score) VALUES ("geekk3@gmail.com","Geek3",36)""")
connection_obj.execute("""INSERT INTO GEEK (Email,Name,Score) VALUES ("geekk4@gmail.com","Geek4",27)""")
connection_obj.execute("""INSERT INTO GEEK (Email,Name,Score) VALUES ("geekk5@gmail.com","Geek5",40)""")
connection_obj.execute("""INSERT INTO GEEK (Email,Name,Score) VALUES ("geekk6@gmail.com","Geek6",14)""")
connection_obj.execute("""INSERT INTO GEEK (Email,Name,Score) VALUES ("geekk7@gmail.com","Geek7",10)""")
 
connection_obj.commit()
 
# Close the connection
connection_obj.close()

Python3

import sqlite3
 
# Connecting to sqlite
# connection object
connection_obj = sqlite3.connect('geek.db')
 
# cursor object
cursor_obj = connection_obj.cursor()
 
 
#delete data
cursor_obj.execute("DELETE FROM GEEK WHERE Score < 15")
 
connection_obj.commit()
# Close the connection
connection_obj.close()

Python3

import sqlite3
 
# Connecting to sqlite
# connection object
connection_obj = sqlite3.connect('geek.db')
 
# cursor object
cursor_obj = connection_obj.cursor()
cursor_obj.execute("SELECT * FROM GEEK")
print(cursor_obj.fetchall())
 
#delete data
'''It will delete all rows from
   the table
'''
cursor_obj.execute("DELETE FROM GEEK")
print()
print("After deleting all rows")
cursor_obj.execute("SELECT * FROM GEEK")
print(cursor_obj.fetchall())
connection_obj.commit()
# Close the connection
connection_obj.close()

输出：

现在我们将创建一个Python程序来删除表中的行：

方法：

导入所需的模块。
使用 sqlite3 模块的 connect()函数与数据库建立连接或创建连接对象。
通过调用 Connection 对象的 cursor() 方法创建一个 Cursor 对象。
最后，触发游标对象上的 execute() 方法，绕过 DELETE 语句作为它的参数。

例1：（删除部分数据）

蟒蛇3

import sqlite3
 
# Connecting to sqlite
# connection object
connection_obj = sqlite3.connect('geek.db')
 
# cursor object
cursor_obj = connection_obj.cursor()
 
 
#delete data
cursor_obj.execute("DELETE FROM GEEK WHERE Score < 15")
 
connection_obj.commit()
# Close the connection
connection_obj.close()

输出：

例2：（删除所有数据）

蟒蛇3

import sqlite3
 
# Connecting to sqlite
# connection object
connection_obj = sqlite3.connect('geek.db')
 
# cursor object
cursor_obj = connection_obj.cursor()
cursor_obj.execute("SELECT * FROM GEEK")
print(cursor_obj.fetchall())
 
#delete data
'''It will delete all rows from
   the table
'''
cursor_obj.execute("DELETE FROM GEEK")
print()
print("After deleting all rows")
cursor_obj.execute("SELECT * FROM GEEK")
print(cursor_obj.fetchall())
connection_obj.commit()
# Close the connection
connection_obj.close()

输出：