One approach to establish a parameter within a plpgsql function for utilization in a bash script is to use a combination of a plpgsql function with an OUT parameter and a programmatic call to the function from the bash script.
Here's an example:
First, create a plpgsql function that takes a parameter and returns its value through an OUT parameter:
CREATE OR REPLACE FUNCTION get_param(p_name text, OUT p_value text)
AS $$
BEGIN
SELECT value INTO p_value FROM parameters WHERE name = p_name;
END;
$$
LANGUAGE plpgsql;
In this example, the function get_param
takes a parameter p_name
and returns its value through the OUT parameter p_value
. The SELECT statement retrieves the value from a parameters
table that presumably stores various parameters.
Next, in your bash script, define a variable to receive the value returned by the plpgsql function using psql
to execute the function programmatically:
#!/bin/bash
PARAM_NAME="some_param"
PARAM_VALUE=$(psql -d <database_name> -U <database_user> -t -A -c "SELECT get_param('$PARAM_NAME')")
echo "Parameter $PARAM_NAME = $PARAM_VALUE"
In this example, we define a bash variable PARAM_NAME
which corresponds to the p_name
parameter in the plpgsql function. We execute the plpgsql function using psql
, passing in the PARAM_NAME
variable, and capture the result into PARAM_VALUE
. Finally, we print out the parameter name and value.
Note that you will need to substitute <database_name>
and <database_user>
with your actual database name and user, and ensure that the appropriate PostgreSQL client tools (e.g. psql
) are installed on your system.
Asked: 2021-10-25 11:00:00 +0000
Seen: 12 times
Last updated: May 30 '22