How do I get tables in postgres using psycopg2?

Question

Can someone please explain how I can get the tables in the current database?

I am using postgresql-8.4 psycopg2.

Answer 1

pg_class stores all the required information.

executing the below query will return user defined tables as a tuple in a list

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()

output:

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

Answer 2

The question is about using python's psycopg2 to do things with postgres. Here are two handy functions:

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 3

you can use this code for 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()

Answer 4

If you use psql, you can type:

\d

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

If you are running SQL, you can type:

SELECT * FROM tables;

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

If you want statistics about their usage, you can type:

SELECT * FROM pg_stat_user_tables;

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

Answer 5

This did the trick for me:

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