如何使用 psycopg2 在 postgres 中獲取表？

Question

有人可以解釋一下如何獲取當前數據庫中的表嗎？

我正在使用 postgresql-8.4 psycopg2。

Answer 1

這對我有用：

cursor.execute("""SELECT table_name FROM information_schema.tables
       WHERE table_schema = 'public'""")
for table in cursor.fetchall():
    print(table)

Answer 2

pg_class 存儲所有必需的信息。

執行以下查詢將用戶定義的表作為列表中的元組返回

conn = psycopg2.connect(conn_string)
cursor = conn.cursor()
cursor.execute("select relname from pg_class where relkind='r' and relname !~ '^(pg_|sql_)';")
print cursor.fetchall()

輸出：

[('table1',), ('table2',), ('table3',)]

Answer 3

問題是關於使用 python 的 psycopg2 用 postgres 做事。 這里有兩個方便的功能：

def table_exists(con, table_str):

    exists = False
    try:
        cur = con.cursor()
        cur.execute("select exists(select relname from pg_class where relname='" + table_str + "')")
        exists = cur.fetchone()[0]
        print exists
        cur.close()
    except psycopg2.Error as e:
        print e
    return exists

def get_table_col_names(con, table_str):

    col_names = []
    try:
        cur = con.cursor()
        cur.execute("select * from " + table_str + " LIMIT 0")
        for desc in cur.description:
            col_names.append(desc[0])        
        cur.close()
    except psycopg2.Error as e:
        print e

    return col_names

Answer 4

這是一個包含connect()參數以及為輸出生成Python list()的Python3片段：

conn = psycopg2.connect(host='localhost', dbname='mySchema',
                        user='myUserName', password='myPassword')
cursor = conn.cursor()

cursor.execute("""SELECT relname FROM pg_class WHERE relkind='r'
                  AND relname !~ '^(pg_|sql_)';""") # "rel" is short for relation.

tables = [i[0] for i in cursor.fetchall()] # A list() of tables.

Answer 5

雖然 Kalu 已經回答了它，但提到的查詢從 postgres 數據庫返回表 + 視圖。 如果您只需要表而不是視圖，那么您可以在查詢中包含 table_type，例如-

        s = "SELECT"
        s += " table_schema"
        s += ", table_name"
        s += " FROM information_schema.tables"
        s += " WHERE"
        s += " ("
        s += " table_schema = '"+SCHEMA+"'"
        s += " AND table_type = 'BASE TABLE'"
        s += " )"
        s += " ORDER BY table_schema, table_name;"

        db_cursor.execute(s)
        list_tables = db_cursor.fetchall()

Answer 6

如果你使用 psql，你可以輸入：

\d

http://www.postgresql.org/docs/9.1/static/app-psql.html

如果您正在運行 SQL，則可以鍵入：

SELECT * FROM tables;

http://www.postgresql.org/docs/current/interactive/information-schema.html

如果您想要有關其使用情況的統計信息，可以鍵入：

SELECT * FROM pg_stat_user_tables;

http://www.postgresql.org/docs/current/interactive/monitoring-stats.html

Answer 7

您可以將此代碼用於python 3

import psycopg2

conn=psycopg2.connect(database="your_database",user="postgres", password="",
host="127.0.0.1", port="5432")

cur = conn.cursor()

cur.execute("select * from your_table")
rows = cur.fetchall()
conn.close()