What is the relationship between a script and story logline?

Richiev put it very well, so there's very little to add. However, one thing worth mentioning is that the power of a logline comes from the inherent conflict in the plot it describes. The best loglines are the ones that use the least adjectives to describe a clear cause and effect relationship between the event, obstacle and goal.

A logline is a brief description of the plot, it is used to sell your script to an industry insider. (As opposed to a tagline which is used to sell the movie to an audience)

The logline should include a lead character, the inciting incident, the lead character's goal and what is standing in the way of the goal (The main conflict) and if possible, it should also have a one or two-word hook.

However, do not give away the end of the story in a logline, nor any big reveal.

While there are formulas to writing a logline, What you want is this, after the reader has read the logline, they should be able to visualize the story in their head. It should not lead to confusion and questions like "Who is the lead character?" "What does the lead character want?" "What separates your story from every other story in this genre?" Or even worse, "I just don't get it"

If this is the response then your logline does not properly reflect the story that is in your script, (the story in your head) -or- your script has major story problems.

I hope this is what you were looking for.

"...story logline..." as opposed to?

In our 'Formula' tab we include explanations of what a logline is and how it works.

In short, a logline is a tool used to describe the major story beats of a plot.