postgresql基础操作

postgresql 基础操作

查询

import psycopg2.extras
import json
conn = psycopg2.connect(database='web_fetching', user='crawler', password='crawler', host='0.0.0.0', port='5432')

cursor = conn.cursor()
# sql = 'ALTER TABLE phone ALTER COLUMN name type varchar(9999) ;'
sql = 'select * from phonedb '
resp = cursor.execute(sql)

err_list = []

rows = cursor.fetchall()
for row in rows:
    print(row)

conn.commit()
conn.close()

创建

import psycopg2.extras
import psycopg2
conn = psycopg2.connect(database='web_fetching', user='crawler', password='crawler', host='0.0.0.0', port='5432')


cursor = conn.cursor()
# sql = 'ALTER TABLE phone ALTER COLUMN id type varchar(9999) ;'

cursor.execute("""CREATE TABLE phonedb 
       (ID INT PRIMARY KEY NOT NULL,
       NAME TEXT ,
       INFO TEXT )"""
               )

conn.commit()
conn.close()

删除表

import psycopg2.extras
conn = psycopg2.connect(database='web_fetching', user='crawler', password='crawler', host='0.0.0.0', port='5432')


cursor = conn.cursor()
# sql = 'ALTER TABLE phone ALTER COLUMN id type varchar(9999) ;'
sql = 'drop table phonedb'
resp = cursor.execute(sql)

# rows = cursor.fetchall()
# for row in rows:
#     print(row)

conn.commit()
conn.close()

print(f'')

查看表结构

import psycopg2.extras
conn = psycopg2.connect(database='web_fetching', user='crawler', password='crawler', host='0.0.0.0', port='5432')

cursor = conn.cursor()
sql = '''
SELECT a.attnum,
a.attname AS field,
t.typname AS type,
a.attlen AS length,
a.atttypmod AS lengthvar,
a.attnotnull AS notnull,
b.description AS comment
FROM pg_class c,
pg_attribute a
LEFT OUTER JOIN pg_description b ON a.attrelid=b.objoid AND a.attnum = b.objsubid,
pg_type t
WHERE c.relname = '库名称'
and a.attnum > 0
and a.attrelid = c.oid
and a.atttypid = t.oid
ORDER BY a.attnum;
'''
# sql = 'delete from phone where id=3'
resp = cursor.execute(sql)

rows = cursor.fetchall()
for row in rows:
    print(row)

conn.commit()
conn.close()

print(f'')