python - 使用psycopg2动态更改python中的数据库（postgresql）

Question

谁能告诉我如何动态更改我刚刚创建的数据库..使用以下代码...我认为在执行此代码期间，我将在默认的 postgres 数据库（即模板数据库）和新数据库之后创建我想在运行时更改我的数据库以进行进一步处理...

    from psycopg2 import connect
    from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT

    dbname = 'db_name'
    con = connect(user ='postgres', host = 'localhost', password = '*****')
    con.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
    cur = con.cursor()
    cur.execute('CREATE DATABASE ' + dbname)
    cur.close()
    con.close()

Answer 1

您可以简单地再次使用database=dbname参数连接。SELECT current_database()注意用于显示我们在哪个数据库上工作以及SELECT * FROM pg_database显示可用数据库的用法：

from psycopg2 import connect
from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT

def show_query(title, qry):
    print('%s' % (title))
    cur.execute(qry)
    for row in cur.fetchall():
        print(row)
    print('')

dbname = 'db_name'
print('connecting to default database ...')
con = connect(user ='postgres', host = 'localhost', password = '*****', port=5492)
con.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
cur = con.cursor()
show_query('current database', 'SELECT current_database()')
cur.execute('CREATE DATABASE ' + dbname)
show_query('available databases', 'SELECT * FROM pg_database')
cur.close()
con.close()

print('connecting to %s ...' % (dbname))
con = connect(user ='postgres', database=dbname, host = 'localhost', password = '*****', port=5492)
cur = con.cursor()
show_query('current database', 'SELECT current_database()')
cur.close()
con.close()