con = psycopg2.connect(database='testdb', user='postgres', password='s$cret') with con: cur = con.cursor() cur.execute("SELECT * FROM cars") rows = cur.fetchall() for row in rows: print(f"{row[0]} {row[1]} {row[2]}") In this example, we retrieve all data from thecars...
pool=AsyncConnectionPool("postgres://user:pass@host/db",min_size=5,max_size=20)asyncdefquery():asyncwithpool.connection()asconn:asyncwithconn.cursor()ascur:awaitcur.execute("SELECT ...")returnawaitcur.fetchall()# 并发执行tasks=[query()for_inrange(100)]results=awaitasyncio.gather(*tasks) ...
import psycopg2 # 创建连接 conn = psycopg2.connect(dbname="your_database_name",user="your_usernam...
db_config = { "dbname": "postgres", # 连接默认数据库以执行系统表查询 "user": "postgres", "password": "postgres", "host": "localhost", "port": 5432 } # 执行查询并打印结果 databases = list_all_databases(db_config) if databases: print("PostgreSQL数据库清单(非模板库):") for idx, d...
打开PostgreSQL 的命令行工具 psql,并登录到默认的postgres用户: psql -U postgres 创建一个新的数据库exampledb: CREATEDATABASE exampledb; 创建表 切换到新创建的数据库exampledb: \c exampledb 接下来,创建一张名为employees的表,包含id,name,age, 和position字段: ...
Python Example to create and manage PostgreSQL Connection Pool Let see how to use theSimpleConnectionPoolclass to create and manage a PostgreSQL connection pool in Python. importpsycopg2frompsycopg2importpooltry: postgreSQL_pool = psycopg2.pool.SimpleConnectionPool(1,20, user="postgres", ...
Following python example demonstrates the usage of WHERE command using python.import psycopg2 #establishing the connection conn = psycopg2.connect( database="mydb", user='postgres', password='password', host='127.0.0.1', port= '5432' ) #Setting auto commit false conn.autocommit = True #...
Let’s take an example of calling a PostgreSQL function from Python. 1) Create a new function First, open the Command Prompt on Windows or Terminal on Unix-like systems and connect to the suppliers database: psql -U postgres -d suppliers Second, execute the following command to create a ...
下面的代码示例创建通向 Postgres 数据库的连接池。 然后,该代码使用cursor.execute函数以及 SQL CREATE TABLE 和 INSERT INTO 语句来创建表并插入数据。 提示 下面的示例代码使用连接池来创建和管理与 PostgreSQL 的连接。 强烈建议使用应用程序端连接池,因为: ...
val = (“John”, “john@example.com”) mycursor.execute(sql, val) mydb.commit()“` 4. 查询数据使用`SELECT`语句可以从表中查询数据。例如,查询`customers`表中的所有记录:“`pythonmycursor.execute(“SELECT * FROM customers”) result = mycursor.fetchall() for row in result: print(row)“`...