So far, we've been focused on storing users and their status updates, but we can use our knowledge of compound primary keys to make it a bit easier to write status updates too. Let's introduce a hashtagging function into the status update composition interface and then autocomplete hashtags as users type them.
First, we'll set up a table to store hashtags using the following query:
CREATE TABLE "hash_tags" ( "prefix" text, "remaining" text, "tag" text, PRIMARY KEY ("prefix", "remaining"));
The structure of our table is a bit unusual, but it will work very well for our purposes. The partition key is a prefix, which we'll use to store the first two letters of each hashtag. The clustering column, remaining ...