Exists check for database and user

-  Added exists check for database and user
-  Added `--dbname "postgres"` in `psql` command
-  Added owner, utf8 encoding, collate and template

Author: coderocker

create-multiple-postgresql-databases.sh

@@ -6,9 +6,9 @@ set -u
 function create_user_and_database() {
 	local database=$1
 	echo "  Creating user and database '$database'"
-	psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" <<-EOSQL
-	    CREATE USER $database;
-	    CREATE DATABASE $database;
+	psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --dbname "postgres" <<-EOSQL
+	    SELECT 'CREATE USER ' || LOWER(TRIM('$database')) AS create_user_query WHERE NOT EXISTS (SELECT FROM pg_catalog.pg_roles WHERE rolname = LOWER(TRIM('$database')));\gexec
+	    SELECT 'CREATE DATABASE ' || LOWER(TRIM('$database')) || ' WITH OWNER "$POSTGRES_USER" ENCODING "UTF8" LC_COLLATE = "en_US.UTF-8" LC_CTYPE = "en_US.UTF-8" TEMPLATE="template0"' AS create_table_query WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = LOWER(TRIM('$database')));\gexec
 	    GRANT ALL PRIVILEGES ON DATABASE $database TO $database;
 EOSQL
 }