Delete all Contents from postgreSQL

Question

i have a Database with a lots of Tables.

is there a way to clear the contents of the Tables without to do that for each Table! i mean a way to iterate the Database Tables List and delete its contents.

Thanx for your help.

Answer 1

A simple database function which iterates over all tables in a schema and clear his content. WARNING: this function clear all tables without asking if you are sure :) Use with caution! No warranty!

CREATE OR REPLACE FUNCTION clear_tables_in_schema(_schemaname TEXT)RETURNS VOID AS
  $$
  DECLARE _tablename TEXT;
  BEGIN
    FOR _tablename IN SELECT tablename FROM pg_catalog.pg_tables WHERE schemaname = _schemaname LOOP
      RAISE INFO 'Clearing table %.%', _schemaname, _tablename ;
      EXECUTE format('TRUNCATE %I.%I CASCADE;', _schemaname, _tablename);
    END LOOP;
    IF NOT FOUND THEN
      RAISE WARNING 'Schema % does not exist', _schemaname;
    END IF;
  END;    
  $$
LANGUAGE plpgsql;
-- Usage:
SELECT clear_tables_in_schema('your_schema');

Answer 2

Something like:

#!/bin/bash

# Save the schema
pg_dump -U user --format plain  --schema-only --file db_schema.sql dbname    

com="psql -h host -U user -d dbname"

$com <<EOF
DROP TABLE foo;
DROP TABLE bar;
DROP TABLE baz;
# ... more tables here ... 
EOF

# Recreate all tables
$com < db_schema.sql