How to use third column as identifier?

I want to draw a diagram from a three column sheet

Input

| Date          | Value         | Identifier |
| ------------- | ------------- | ---------- |
| 01-04-2014    | 1             | John       |
| 01-04-2014    | 2             | Maja       |
| 01-04-2014    | 27            | Jim        |
| 02-04-2014    | 32            | John       |
| 02-04-2014    | 12            | Maja       |
| 02-04-2014    | 5             | Jim        |
| ...           |               |            |

Expected output:

An independently line per identifier. Value on Y, Date on X.

How do I set this up in LibreOffice - Calc? I’m kind of overwhelmed of it
Oh and I don’t want to use the identifier as column header
I’m using LibreOffice 4.1

Why do you not want the identifiers as column header? It is very easy to generate a derived table using Data > Pivot Table.
Mark the source data and generate a Pivot Table with Date in ‘Row fields’, Identifier in ‘Column fields’, and Value in ‘Data fields’. For your chart you need no totals, but you might be interested in the totals for other reasons. The Pivot Table converts the linear table into a cross table. Then mark the data from the Pivot Table and generate your chart. Example: Ask 2014-05-02 33421 .ods

works fine, thanks!