Passing arguments to psql

Question

I'm running a plpgsql script in Postgres 8.3 - I would like to pass arguments to this script via psql. I'm currently executing the script like:

psql -d database -u user -f update_file.sql 

I came across This link which explains PGOPTIONS environment variable, but that doesn't work for "custom" arguments. i.e. I receive an error because the setting isn't listed in the postgres.conf file.

-bash-3.2$ export PGOPTIONS='--pretend=true'
-bash-3.2$ psql -d my_db -f update_database.sql
psql: FATAL:  unrecognized configuration parameter "pretend"

Any other ideas? Ideally I'd like to avoid environment variables...

Answer 1

Strictly speaking, there is no such thing as a "plpgsql script" - PL/pgSQL is the default procedural language of PostgreSQL. It's either an SQL script or a plpgsql function / procedure. Your example seems to indicate an SQL script.

You could create a (server-side ) plpgsql (or sql) function instead, that takes any number of arguments. It's very simple as long as the arguments are values. It gets a bit more complicated if the arguments include identifiers. Then you'll have to use PL/pgSQL with dynamic SQL and EXECUTE.

PL/pgSQL is pre-installed by default in PostgreSQL 9.0 or later. You have to install it once per database in Postgres 8.3, though:

CREATE LANGUGAGE plpgsql;

Speaking of the version: you should consider upgrading to a current version of PostgreSQL. v8.3 is very old by now - updates will be discontinued (end-of-life) early in 2013.

Since you seem to have a ready SQL script I'll demonstrate an SQL function. Simple dummy function with two integer arguments:

CREATE OR REPLACE FUNCTION func(int, int)
    LANGUAGE sql RETURNS void AS 
$BODY$
    UPDATE mytbl1 SET col1 = $1 WHERE id = $2;
    UPDATE mytbl2 SET col1 = $1 WHERE id = $2;
$BODY$;

You can find many more sophisticated examples for plpgsql here on dba.SE or on stackoverflow.

You can call this function and hand in parameters in a shell script: Basic example for a call in a shell script that uses input parameters for integer parameters (no single-quotes around the value needed):

psql mydb -c "SELECT func($1, $2)"

Or with any data type:

psql mydb -c "SELECT func2('$1'::text, '$2'::numeric)"

-c executes one command string and then exits. More about command line arguments of psql in the manual.

Answer 2

This is not very elegant but it works (pseudocode):

cat <<EOF
   UPDATE tablename SET field=$arg1 WHERE field = $arg2;
EOF | psql database

Answer 3

Try -v:

$ psql -U postgres -v something=\'blah-blah\'
psql (9.1.3)
Type "help" for help.

postgres=# select :something;
 ?column?
----------
 blah-blah
(1 row)

If you want to use current_setting and SET or setval, you have to append a row to postgresql.conf to add the option.