Insert multiple values with foreign key Postgresql - sql

Question

I am having trouble figuring out how to insert multiple values to a table, which checks if another table has the needed values stored. I am currently doing this in a PostgreSQL server, but will be implementing it in PreparedStatements for my java program.
user_id is a foreign key which references the primary in mock2. I have been trying to check if mock2 has values ('foo1', 'bar1') and ('foo2', 'bar2').
After this I am trying to insert new values into mock1 which would have a date and integer value and reference the primary key of the row in mock2 to the foreign key in mock1.
mock1 table looks like this:
===============================
| date | time | user_id |
| date | integer | integer |
| | | |
And the table mock2 is:
==================================
| Id | name | program |
| integer | text | test |
Id is a primary key for the table and the name is UNIQUE.
I've been playing around with this solution https://dba.stackexchange.com/questions/46410/how-do-i-insert-a-row-which-contains-a-foreign-key
However, I haven't been able to make it work. Could someone please point out what the correct syntax is for this, I would be really appreciative.
EDIT:
The create table statements are:
CREATE TABLE mock2(
id SERIAL PRIMARY KEY UNIQUE,
name text NOT NULL,
program text NOT NULL UNIQUE
);
and
CREATE TABLE mock1(
date date,
time_spent INTEGER,
user_id integer REFERENCES mock2(Id) NOT NULL);

Answer 1

Ok so I found an answer to my own question.
WITH ins (date,time_spent, id) AS
( VALUES
( '22/08/2012', 170, (SELECT id FROM mock3 WHERE program ='bar'))
)
INSERT INTO mock4
(date, time_spent, user_id)
SELECT
ins.date, ins.time_spent, mock3.id
FROM
mock3 JOIN ins
ON ins.id = mock3.id ;
I was trying to take the 2 values from the first table, match these and then insert 2 new values to the next table, but I realised that I should be using the Primary and Foreign keys to my advantage.
I instead now JOIN on the ID and then just select the key I need by searching it from the values with (SELECT id FROM mock3 WHERE program ='bar') in the third row.