创建数据库实例
from main import SQLiteDB
db = SQLiteDB("example.db")
使用execute直接执行SQL
db.execute("INSERT INTO user (name, amount, createtime) VALUES (?, ?, ?)",("张三", 25.6, '2023-07-01 15:25:30'))
创建表
# 创建表
db.execute("""
CREATE TABLE users(
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
age INTEGER,
email TEXT UNIQUE,
created_at TEXT DEFAULT (datetime('now', 'localtime'))
);
""")
插入示例
# 单个插入
db.insert("user",['name', 'amount', 'createtime'],('李四', 25.6, '2023-07-01 15:25:30'))
# 元组列表批量插入
fields = ['name', 'amount', 'createtime']
values = [
('用户1', 22, '2024-11-12 12:13:11'),
('用户2', 23, '2024-11-12 12:13:11'),
('用户3', 24, '2024-11-12 12:13:11')
]
db.batch_insert('user', fields, values)
# 字典列表批量插入
users_dict = [
{'name': '小明', 'amount': 22, 'createtime': '2024-11-12 12:13:11'},
{'name': '小红', 'amount': 24, 'createtime': '2024-11-12 12:13:11'},
{'name': '小张', 'amount': 26, 'createtime': '2024-11-12 12:13:11'}
]
db.insert_many_dict('user', users_dict)
删除示例
# 按条件删除
affected_rows = db.delete("user", "age > ?", (30,))
# 按ID删除
db.delete_by_id("user", 1)
# 批量删除
id_list = [1, 2, 3, 4, 5]
db.delete_many("user", id_list)
# 清空表
db.truncate_table("user")
修改示例
# 基础更新
db.update('users', ['name', 'age'], ('张三', 25), 'id = ?', (1,))
# 通过ID更新
db.update_by_id('users', ['name', 'age'], ('张三', 25), 1)
# 使用字典更新
db.update_dict('users', {'name': '张三', 'age': 25}, 'id = ?', (1,))
# 批量更新字典数据
dict_list = [
{'id': 1, 'name': '张三', 'age': 25, 'email': 'zhangsan@example.com'},
{'id': 2, 'name': '李四', 'age': 30, 'email': 'lisi@example.com'}
]
db.batch_update_dict('users', dict_list)
# 批量更新
values_list = [
('张三', 25, 1),
('李四', 30, 2)
]
db.batch_update('users', ['name', 'age'], values_list)
查询示例
# 查询单条记录
result = db.fetch_one("SELECT * FROM user WHERE name = ?", ("张三",))
# 模糊匹配
msg = "你好"
result = db.fetch_one("SELECT * FROM keyword_data WHERE keyword LIKE ?", (f"%{msg}%",))
# 分页查询
db.fetch_page("SELECT * FROM user", 3, 2)
# 查询多条记录
results = db.fetch_all("SELECT * FROM user LIMIT 5")
for row in results:
print(row)
# 条件查询
results = db.fetch_all("SELECT * FROM user WHERE amount > ?", (20,))
for row in results:
print(row)
联表查询示例
假设有两个表：user和orders
内连接查询示例
sql = """
SELECT u.name, o.order_number, o.amount
FROM user u
INNER JOIN orders o ON u.id = o.user_id
WHERE o.amount > ?
"""
results = db.fetch_all(sql, (100,))
for row in results:
print(row)
左连接查询示例
sql = """
SELECT u.name, COUNT(o.id) as order_count
FROM user u
LEFT JOIN orders o ON u.id = o.user_id
GROUP BY u.id
"""
results = db.fetch_all(sql)
for row in results:
print(row)
SQLiteDB
import sqlite3
class SQLiteDB:
def __init__(self, db_name):
"""初始化数据库连接"""
self.conn = None
self.cursor = None
try:
self.conn = sqlite3.connect(db_name)
self.cursor = self.conn.cursor()
except sqlite3.Error as e:
print(f"连接数据库时出错: {e}")
def execute(self, sql, params=None):
"""执行SQL查询
参数:
sql: SQL语句
params: SQL参数，用于参数化查询
返回:
执行成功返回True，失败返回False
"""
try:
if params:
self.cursor.execute(sql, params)
else:
self.cursor.execute(sql)
self.conn.commit()
return True
except sqlite3.Error as e:
print(f"执行查询时出错: {e}")
return False
# 创建表
def create_table(self, table_name, fields):
"""创建数据表
参数:
table_name: 表名
fields: 字段定义列表，每个元素是一个元组 (字段名, 类型定义)
返回:
执行成功返回True，失败返回False
"""
try:
fields_str = ', '.join([f"{name} {definition}" for name, definition in fields])
sql = f"CREATE TABLE IF NOT EXISTS {table_name} ({fields_str})"
return self.execute(sql)
except sqlite3.Error as e:
print(f"创建表时出错: {e}")
return False
# 插入##########################################
def insert(self, table_name, fields, values):
"""插入数据
参数:
table_name: 表名
fields: 字段名列表，例如 ['name', 'age']
values: 值列表，例如 ('张三', 25)
返回:
执行成功返回True，失败返回False
"""
try:
# 构建SQL语句
placeholders = ','.join(['?' for _ in fields])
fields_str = ','.join(fields)
sql = f"INSERT INTO {table_name} ({fields_str}) VALUES({placeholders})"
return self.execute(sql, values)
except sqlite3.Error as e:
print(f"插入数据时出错: {e}")
self.conn.rollback() # 发生错误时回滚
return False
# 批量插入1
def batch_insert(self, table_name, fields, values_list):
"""批量插入数据
参数:
table_name: 表名
fields: 字段名列表，例如 ['name', 'age']
values_list: 值列表，每个元素是一个元组，例如 [('张三', 25), ('李四', 30)]
返回:
执行成功返回True，失败返回False
"""
try:
# 构建SQL语句
placeholders = ','.join(['?' for _ in fields])
fields_str = ','.join(fields)
sql = f"INSERT INTO {table_name} ({fields_str}) VALUES ({placeholders})"
# 执行批量插入
self.cursor.executemany(sql, values_list)
self.conn.commit()
return True
except sqlite3.Error as e:
print(f"批量插入数据时出错: {e}")
self.conn.rollback() # 发生错误时回滚
return False
# 批量插入2
def insert_many_dict(self, table_name, dict_list):
"""使用字典列表批量插入数据
参数:
table_name: 表名
dict_list: 字典列表，每个字典代表一行数据，例如：
[{'name': '张三', 'age': 25}, {'name': '李四', 'age': 30}]
返回:
执行成功返回True，失败返回False
"""
if not dict_list:
return False
try:
# 从第一个字典获取字段名
fields = list(dict_list[0].keys())
# 转换字典列表为值列表
values_list = [tuple(d.values()) for d in dict_list]
return self.batch_insert(table_name, fields, values_list)
except Exception as e:
print(f"处理字典数据时出错: {e}")
return False
############################################################
# 删除###########################################
def delete(self, table_name, condition, params=None):
"""删除数据
参数:
table_name: 表名
condition: WHERE条件语句，例如 "age > ?" 或 "name = ?"
params: 条件参数，例如 (20,) 或 ('张三',)
返回:
执行成功返回受影响的行数，失败返回-1
"""
try:
sql = f"DELETE FROM {table_name} WHERE {condition}"
self.cursor.execute(sql, params or ())
self.conn.commit()
return self.cursor.rowcount
except sqlite3.Error as e:
print(f"删除数据时出错: {e}")
self.conn.rollback()
return -1
def delete_by_id(self, table_name, id_value, id_field='id'):
"""根据ID删除数据
参数:
table_name: 表名
id_value: ID值
id_field: ID字段名，默认为'id'
返回:
执行成功返回受影响的行数，失败返回-1
"""
return self.delete(table_name, f"{id_field} = ?", (id_value,))
def delete_many(self, table_name, id_list, id_field='id'):
"""批量删除数据
参数:
table_name: 表名
id_list: ID列表
id_field: ID字段名，默认为'id'
返回:
执行成功返回受影响的行数，失败返回-1
"""
try:
placeholders = ','.join(['?' for _ in id_list])
sql = f"DELETE FROM {table_name} WHERE {id_field} IN ({placeholders})"
self.cursor.execute(sql, id_list)
self.conn.commit()
return self.cursor.rowcount
except sqlite3.Error as e:
print(f"批量删除数据时出错: {e}")
self.conn.rollback()
return -1
def truncate_table(self, table_name):
"""清空表数据
参数:
table_name: 表名
返回:
执行成功返回True，失败返回False
"""
try:
self.cursor.execute(f"DELETE FROM {table_name}")
self.conn.commit()
return True
except sqlite3.Error as e:
print(f"清空表数据时出错: {e}")
self.conn.rollback()
return False
############################################################
# 更新###########################################
def update(self, table_name, fields, values, condition, condition_params=None):
"""更新数据
参数:
table_name: 表名
fields: 要更新的字段列表，例如 ['name', 'age']
values: 新的值列表，例如 ('张三', 25)
condition: WHERE条件语句，例如 "id = ?"
condition_params: 条件参数，例如 (1,)
返回:
执行成功返回受影响的行数，失败返回-1
"""
try:
# 构建SET子句
set_clause = ','.join([f"{field} = ?" for field in fields])
sql = f"UPDATE {table_name} SET {set_clause} WHERE {condition}"
# 合并values和condition_params
params = list(values)
if condition_params:
params.extend(condition_params)
self.cursor.execute(sql, params)
self.conn.commit()
return self.cursor.rowcount
except sqlite3.Error as e:
print(f"更新数据时出错: {e}")
self.conn.rollback()
return -1
def update_by_id(self, table_name, fields, values, id_value, id_field='id'):
"""根据ID更新数据
参数:
table_name: 表名
fields: 要更新的字段列表，例如 ['name', 'age']
values: 新的值列表，例如 ('张三', 25)
id_value: ID值
id_field: ID字段名，默认为'id'
返回:
执行成功返回受影响的行数，失败返回-1
"""
return self.update(table_name, fields, values, f"{id_field} = ?", (id_value,))
def update_dict(self, table_name, update_dict, condition, condition_params=None):
"""使用字典更新数据
参数:
table_name: 表名
update_dict: 要更新的字段和值的字典，例如 {'name': '张三', 'age': 25}
condition: WHERE条件语句，例如 "id = ?"
condition_params: 条件参数，例如 (1,)
返回:
执行成功返回受影响的行数，失败返回-1
"""
fields = list(update_dict.keys())
values = list(update_dict.values())
return self.update(table_name, fields, values, condition, condition_params)
def batch_update_dict(self, table_name, dict_list, id_field='id'):
"""使用字典列表批量更新数据
参数:
table_name: 表名
dict_list: 字典列表，每个字典必须包含id_field字段，例如：
[{'id': 1, 'name': '张三', 'age': 25},
{'id': 2, 'name': '李四', 'age': 30}]
id_field: ID字段名，默认为'id'
返回:
执行成功返回受影响的行数，失败返回-1
"""
if not dict_list:
return 0
try:
# 从第一个字典获取所有字段名（排除ID字段）
fields = [f for f in dict_list[0].keys() if f != id_field]
# 转换字典列表为值列表
values_list = []
for d in dict_list:
# 确保字典中包含ID字段
if id_field not in d:
raise ValueError(f"字典中缺少 {id_field} 字段")
# 构建值元组：先添加要更新的字段值，最后添加ID值
values = tuple(d[f] for f in fields)
values += (d[id_field],)
values_list.append(values)
return self.batch_update(table_name, fields, values_list, id_field)
except Exception as e:
print(f"批量更新字典数据时出错: {e}")
return -1
def batch_update(self, table_name, fields, values_list, id_field='id'):
"""批量更新数据
参数:
table_name: 表名
fields: 要更新的字段列表，例如 ['name', 'age']
values_list: 值列表，每个元素是一个元组，包含新值和ID，例如 [('张三', 25, 1), ('李四', 30, 2)]
id_field: ID字段名，默认为'id'
返回:
执行成功返回受影响的行数，失败返回-1
"""
try:
# 构建SET子句
set_clause = ','.join([f"{field} = ?" for field in fields])
sql = f"UPDATE {table_name} SET {set_clause} WHERE {id_field} = ?"
self.cursor.executemany(sql, values_list)
self.conn.commit()
return self.cursor.rowcount
except sqlite3.Error as e:
print(f"批量更新数据时出错: {e}")
self.conn.rollback()
return -1
############################################################
# 查询
def fetch_all(self, sql, params=None):
"""获取所有查询结果
参数:
sql: SQL查询语句
params: SQL参数，用于参数化查询
返回:
查询结果列表，失败返回空列表
"""
try:
if params:
self.cursor.execute(sql, params)
else:
self.cursor.execute(sql)
return self.cursor.fetchall()
except sqlite3.Error as e:
print(f"获取数据时出错: {e}")
return []
# 分页查询
def fetch_page(self, sql, page_num, page_size, params=None):
page_sql = f" limit {(page_num - 1) * page_size},{page_size}"
print(sql + page_sql)
return self.fetch_all(sql + page_sql, params)
def fetch_one(self, sql, params=None):
"""获取单条查询结果
参数:
sql: SQL查询语句
params: SQL参数，用于参数化查询
返回:
单条查询结果，失败返回None
"""
try:
if params:
self.cursor.execute(sql, params)
else:
self.cursor.execute(sql)
return self.cursor.fetchone()
except sqlite3.Error as e:
print(f"获取数据时出错: {e}")
return None
############################################################
# 销毁对象时关闭数据库连接
def __del__(self):
try:
self.execute("VACUUM;")
"""关闭数据库连接"""
if self.conn:
self.cursor.close()
self.conn.close()
except sqlite3.Error as e:
pass
常用sql
清空表数据,重置id自增到0
delete from 表名;
DELETE FROM sqlite_sequence WHERE name = '表名';
