Drop A Template Database From PostgreSQL

postgres=# DROP DATABASE tempdb;
ERROR:  cannot drop a template database

METHOD 1:

• if we want to drop any database means you need to set datistemplate=false
• if you want to connect to template0 you need to set dataallowcomm=true

temp0=# UPDATE pg_database SET datistemplate='false' WHERE datname='temp0';
UPDATE 1

--Becouse you cannot drop from connected database temp0 if you want to drop the database you need to connect as another database and drop the temp0 database 

temp0=# DROP DATABASE temp0;                                               
ERROR:  cannot drop the currently open database

postgres=# DROP DATABASE tempdb;
DROP DATABASE

METHOD 2:

postgres=# create database temp11 is_template true;
CREATE DATABASE

postgres=# drop database tempdb;
ERROR:  cannot drop a template database

postgres=# alter database tempdb is_template false;
ALTER DATABASE

postgres=# drop database tempdb;
DROP DATABASE