In a website that ALL webpages are of index.php?id=1, index.php?id=2, index.php?id=3,

[traq]

^my example (and thetestingsite's alternative above) do not use a database at all, so no, there is no "encoding" (inserting, retrieving, updating, etc.) for a database.

[molendijk]

You can do something similar using javascript, see this.
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Arie Molendijk.