What are the common databases in python? Databases are roughly divided into two categories. The first category includes relational databases, and the second category is non-relational databases. The following is an introduction to the relevant knowledge of these two types of databases.
Including relational databases: sqlite, mysql, mssql
Non-relational databases: MongoDB, Redis
1. Connect to Sqlite
import sqlite3
import traceback
try:
# 如果表不存在,就创建
with sqlite3.connect('test.db') as conn:
print("Opened database successfully")
# 删除表
conn.execute("DROP TABLE IF EXISTS COMPANY")
# 创建表
sql = """
CREATE TABLE IF NOT EXISTS COMPANY
(ID INTEGER PRIMARY KEY AUTOINCREMENT,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(50),
SALARY REAL);
"""
conn.execute(sql)
print("create table successfully")
# 添加数据
conn.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES (?, ?, ?, ? )",
[('Paul', 32, 'California', 20000.00),
('Allen', 25, 'Texas', 15000.00),
('Teddy', 23, 'Norway', 20000.00),
('Mark', 25, 'Rich-Mond ', 65000.00),
('David', 27, 'Texas', 85000.00),
('Kim', 22, 'South-Hall', 45000.00),
('James', 24, 'Houston', 10000.00)])
# conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
# VALUES ( 'Paul', 32, 'California', 20000.00 )")
#
# conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
# VALUES ('Allen', 25, 'Texas', 15000.00 )")
#
# conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
# VALUES ('Teddy', 23, 'Norway', 20000.00 )")
#
# conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
# VALUES ( 'Mark', 25, 'Rich-Mond ', 65000.00 )")
#
# conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
# VALUES ( 'David', 27, 'Texas', 85000.00 )");
#
# conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
# VALUES ( 'Kim', 22, 'South-Hall', 45000.00 )")
#
# conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
# VALUES ( 'James', 24, 'Houston', 10000.00 )")
# 提交,否则重新运行程序时,表中无数据
conn.commit()
print("insert successfully")
# 查询表
sql = """
select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
"""
result = conn.execute(sql)
for row in result:
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("id", row[0])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row[1]))
print("%-10s %s" % ("age", row[2]))
print("%-10s %s" % ("address", row[3]))
print("%-10s %.2f" % ("salary", row[4]))
# or
# print('{:10s} {:.2f}'.format("salary", row[4]))
except sqlite3.Error as e:
print("sqlite3 Error:", e)
traceback.print_exc()2. Connect mysql
Related recommendations: "python video tutorial"
2.2 Using MySQLdb
2.1 Using _mysql in the mysqldb library
import MySQLdb
from contextlib import closing
import traceback
try:
# 获取一个数据库连接
with closing(MySQLdb.connect(host='localhost', user='root', passwd='root', db='test', port=3306,charset='utf8')) as conn:
print("connect database successfully")
with closing(conn.cursor()) as cur:
# 删除表
cur.execute("DROP TABLE IF EXISTS COMPANY")
# 创建表
sql = """
CREATE TABLE IF NOT EXISTS COMPANY
(ID INTEGER PRIMARY KEY NOT NULL auto_increment,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(50),
SALARY REAL);
"""
cur.execute(sql)
print("create table successfully")
# 添加数据
# 在一个conn.execute里面里面执行多个sql语句是非法的
cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
[('Paul', 32, 'California', 20000.00),
('Allen', 25, 'Texas', 15000.00),
('Teddy', 23, 'Norway', 20000.00),
('Mark', 25, 'Rich-Mond ', 65000.00),
('David', 27, 'Texas', 85000.00),
('Kim', 22, 'South-Hall', 45000.00),
('James', 24, 'Houston', 10000.00)])
# 提交,否则重新运行程序时,表中无数据
conn.commit()
print("insert successfully")
# 查询表
sql = """
select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
"""
cur.execute(sql)
for row in cur.fetchall():
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("id", row[0])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row[1]))
print("%-10s %s" % ("age", row[2]))
print("%-10s %s" % ("address", row[3]))
print("%-10s %s" % ("salary", row[4]))
except MySQLdb.Error as e:
print("Mysql Error:", e)
traceback.print_exc() # 打印错误栈信息2.2 Using MySQLdb
import MySQLdb
from contextlib import closing
import traceback
try:
# 获取一个数据库连接
with closing(MySQLdb.connect(host='localhost', user='root', passwd='root', db='test', port=3306,charset='utf8')) as conn:
print("connect database successfully")
with closing(conn.cursor()) as cur:
# 删除表
cur.execute("DROP TABLE IF EXISTS COMPANY")
# 创建表
sql = """
CREATE TABLE IF NOT EXISTS COMPANY
(ID INTEGER PRIMARY KEY NOT NULL auto_increment,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(50),
SALARY REAL);
"""
cur.execute(sql)
print("create table successfully")
# 添加数据
# 在一个conn.execute里面里面执行多个sql语句是非法的
cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
[('Paul', 32, 'California', 20000.00),
('Allen', 25, 'Texas', 15000.00),
('Teddy', 23, 'Norway', 20000.00),
('Mark', 25, 'Rich-Mond ', 65000.00),
('David', 27, 'Texas', 85000.00),
('Kim', 22, 'South-Hall', 45000.00),
('James', 24, 'Houston', 10000.00)])
# 提交,否则重新运行程序时,表中无数据
conn.commit()
print("insert successfully")
# 查询表
sql = """
select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
"""
cur.execute(sql)
for row in cur.fetchall():
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("id", row[0])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row[1]))
print("%-10s %s" % ("age", row[2]))
print("%-10s %s" % ("address", row[3]))
print("%-10s %s" % ("salary", row[4]))
except MySQLdb.Error as e:
print("Mysql Error:", e)
traceback.print_exc() # 打印错误栈信息2.3 Use pymysql
Section 2.1 and 2.2 use MySQLdb, which does not support Python3.x
pymysql has better support for Python2.x and Python3.x
import pymysql
from contextlib import closing
import traceback
try:
# 获取一个数据库连接,with关键字 表示退出时,conn自动关闭
# with 嵌套上一层的with 要使用closing()
with closing(pymysql.connect(host='localhost', user='root', passwd='root', db='test', port=3306,
charset='utf8')) as conn:
print("connect database successfully")
# 获取游标,with关键字 表示退出时,cur自动关闭
with conn.cursor() as cur:
# 删除表
cur.execute("DROP TABLE IF EXISTS COMPANY")
# 创建表
sql = """
CREATE TABLE IF NOT EXISTS COMPANY
(ID INTEGER PRIMARY KEY NOT NULL auto_increment,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(50),
SALARY REAL);
"""
cur.execute(sql)
print("create table successfully")
# 添加数据
# 在一个conn.execute里面里面执行多个sql语句是非法的
cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
[('Paul', 32, 'California', 20000.00),
('Allen', 25, 'Texas', 15000.00),
('Teddy', 23, 'Norway', 20000.00),
('Mark', 25, 'Rich-Mond ', 65000.00),
('David', 27, 'Texas', 85000.00),
('Kim', 22, 'South-Hall', 45000.00),
('James', 24, 'Houston', 10000.00)])
# 提交,否则重新运行程序时,表中无数据
conn.commit()
print("insert successfully")
# 查询表
sql = """
select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
"""
cur.execute(sql)
for row in cur.fetchall():
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("id", row[0])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row[1]))
print("%-10s %s" % ("age", row[2]))
print("%-10s %s" % ("address", row[3]))
print("%-10s %s" % ("salary", row[4]))
except pymysql.Error as e:
print("Mysql Error:", e)
traceback.print_exc()3.Connect to mssql
import pymssql
from contextlib import closing
try:
# 先要保证数据库中有test数据库
# 获取一个数据库连接,with关键字 表示退出时,conn自动关闭
# with 嵌套上一层的with 要使用closing()
with closing(pymssql.connect(host='192.168.100.114', user='sa', password='sa12345', database='test', port=1433,
charset='utf8')) as conn:
print("connect database successfully")
# 获取游标,with关键字 表示退出时,cur自动关闭
with conn.cursor() as cur:
# 删除表
cur.execute(
'''if exists (select 1 from sys.objects where name='COMPANY' and type='U') drop table COMPANY''')
# 创建表
sql = """
CREATE TABLE COMPANY
(ID INT IDENTITY(1,1) PRIMARY KEY NOT NULL ,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(50),
SALARY REAL);
"""
cur.execute(sql)
print("create table successfully")
# 添加数据
# 在一个conn.execute里面里面执行多个sql语句是非法的
cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
[('Paul', 32, 'California', 20000.00),
('Allen', 25, 'Texas', 15000.00),
('Teddy', 23, 'Norway', 20000.00),
('Mark', 25, 'Rich-Mond', 65000.00),
('David', 27, 'Texas', 85000.00),
('Kim', 22, 'South-Hall', 45000.00),
('James', 24, 'Houston', 10000.00)])
# 提交,否则重新运行程序时,表中无数据
conn.commit()
print("insert successfully")
# 查询表
sql = """
select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
"""
cur.execute(sql)
for row in cur.fetchall():
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("id", row[0])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row[1]))
print("%-10s %s" % ("age", row[2]))
print("%-10s %s" % ("address", row[3]))
print("%-10s %s" % ("salary", row[4]))
except pymssql.Error as e:
print("mssql Error:", e)
# traceback.print_exc()4.Connect to MongoDB
import pymongo
from pymongo.mongo_client import MongoClient
import pymongo.errors
import traceback
try:
# 连接到 mongodb 服务
mongoClient = MongoClient('localhost', 27017)
# 连接到数据库
mongoDatabase = mongoClient.test
print("connect database successfully")
# 获取集合
mongoCollection = mongoDatabase.COMPANY
# 移除所有数据
mongoCollection.remove()
# 添加数据
mongoCollection.insert_many([{"Name": "Paul", "Age": "32", "Address": "California", "Salary": "20000.00"},
{"Name": "Allen", "Age": "25", "Address": "Texas", "Salary": "15000.00"},
{"Name": "Teddy", "Age": "23", "Address": "Norway", "Salary": "20000.00"},
{"Name": "Mark", "Age": "25", "Address": "Rich-Mond", "Salary": "65000.00"},
{"Name": "David", "Age": "27", "Address": "Texas", "Salary": "85000.00"},
{"Name": "Kim", "Age": "22", "Address": "South-Hall", "Salary": "45000.00"},
{"Name": "James", "Age": "24", "Address": "Houston", "Salary": "10000.00"}, ])
#获取集合中的值
for row in mongoCollection.find():
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("_id", row['_id'])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row['Name']))
print("%-10s %s" % ("age", row['Age']))
print("%-10s %s" % ("address", row['Address']))
print("%-10s %s" % ("salary", row['Salary']))
print('\n\n\n')
# 使id自增
mongoCollection.remove()
# 创建计数表
mongoDatabase.counters.save({"_id": "people_id", "sequence_value": 0})
# 创建存储过程
mongoDatabase.system_js.getSequenceValue = '''function getSequenceValue(sequenceName){
var sequenceDocument = db.counters.findAndModify({
query: {_id: sequenceName},
update: {$inc:{sequence_value: 1}},
new:true
});
return sequenceDocument.sequence_value;
}'''
mongoCollection.insert_many(
[{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Paul", "Age": "32",
"Address": "California", "Salary": "20000.00"},
{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Allen", "Age": "25",
"Address": "Texas", "Salary": "15000.00"},
{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Teddy", "Age": "23",
"Address": "Norway", "Salary": "20000.00"},
{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Mark", "Age": "25",
"Address": "Rich-Mond", "Salary": "65000.00"},
{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "David", "Age": "27",
"Address": "Texas", "Salary": "85000.00"},
{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Kim", "Age": "22",
"Address": "South-Hall", "Salary": "45000.00"},
{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "James", "Age": "24",
"Address": "Houston", "Salary": "10000.00"}, ])
for row in mongoCollection.find():
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("_id", int(row['_id']))) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row['Name']))
print("%-10s %s" % ("age", row['Age']))
print("%-10s %s" % ("address", row['Address']))
print("%-10s %s" % ("salary", row['Salary']))
except pymongo.errors.PyMongoError as e:
print("mongo Error:", e)
traceback.print_exc()5.Connect to Redis
5.1Using redis
import redis
r = redis.Redis(host='localhost', port=6379, db=0, password="12345")
print("connect", r.ping())
# 看信息
info = r.info()
# or 查看部分信息
# info = r.info("Server")
# 输出信息
items = info.items()
for i, (key, value) in enumerate(items):
print("item %s----%s:%s" % (i, key, value))
# 删除键和对应的值
r.delete("company")
# 可以一次性push一条或多条数据
r.rpush("company", {"id": 1, "Name": "Paul", "Age": "32", "Address": "California", "Salary": "20000.00"},
{"id": 2, "Name": "Allen", "Age": "25", "Address": "Texas", "Salary": "15000.00"},
{"id": 3, "Name": "Teddy", "Age": "23", "Address": "Norway", "Salary": "20000.00"})
r.rpush("company", {"id": 4, "Name": "Mark", "Age": "25", "Address": "Rich-Mond", "Salary": "65000.00"})
r.rpush("company", {"id": 5, "Name": "David", "Age": "27", "Address": "Texas", "Salary": "85000.00"})
r.rpush("company", {"id": 6, "Name": "Kim", "Age": "22", "Address": "South-Hall", "Salary": "45000.00"})
r.rpush("company", {"id": 7, "Name": "James", "Age": "24", "Address": "Houston", "Salary": "10000.00"})
# eval用来将dict格式的字符串转换成dict
for row in map(lambda x: eval(x), r.lrange("company", 0, r.llen("company"))):
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("_id", row['id'])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row['Name']))
print("%-10s %s" % ("age", row['Age']))
print("%-10s %s" % ("address", row['Address']))
print("%-10s %s" % ("salary", row['Salary']))
# 关闭当前连接
# r.shutdown() #这个是关闭redis服务端5.2Using pyredis
import pyredis
r = pyredis.Client(host='localhost', port=6379, database=0, password="12345")
print("connect", r.ping().decode("utf-8"))
# 看信息
# info = r.execute("info").decode()
# or 查看部分信息
info = r.execute("info", "Server").decode()
# 输出信息
print(info)
# 删除键和对应的值
r.delete("company")
# 可以一次性push一条或多条数据
r.rpush("company", '''{"id": 1, "Name": "Paul", "Age": "32", "Address": "California", "Salary": "20000.00"}''',
'''{"id": 2, "Name": "Allen", "Age": "25", "Address": "Texas", "Salary": "15000.00"}''',
'''{"id": 3, "Name": "Teddy", "Age": "23", "Address": "Norway", "Salary": "20000.00"}''')
r.rpush("company", '''{"id": 4, "Name": "Mark", "Age": "25", "Address": "Rich-Mond", "Salary": "65000.00"}''')
r.rpush("company", '''{"id": 5, "Name": "David", "Age": "27", "Address": "Texas", "Salary": "85000.00"}''')
r.rpush("company", '''{"id": 6, "Name": "Kim", "Age": "22", "Address": "South-Hall", "Salary": "45000.00"}''')
r.rpush("company", '''{"id": 7, "Name": "James", "Age": "24", "Address": "Houston", "Salary": "10000.00"}''')
# eval用来将dict格式的字符串转换成dict
for row in map(lambda x: eval(x), r.lrange("company", 0, r.llen("company"))):
print("-" * 50) # 输出50个-,作为分界线
print("%-10s %s" % ("_id", row['id'])) # 字段名固定10位宽度,并且左对齐
print("%-10s %s" % ("name", row['Name']))
print("%-10s %s" % ("age", row['Age']))
print("%-10s %s" % ("address", row['Address']))
print("%-10s %s" % ("salary", row['Salary']))
# 关闭当前连接
r.close()The above is the detailed content of What are the common databases in python?. For more information, please follow other related articles on the PHP Chinese website!
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