Organizing Related Data - Learning Apache Cassandra - page 49

Creating a table with a compound primary key
The syntax for creating tables with compound primary keys is a bit different from the
single-column primary key syntax we saw in the previous chapter. We create a
user_status_updates table with a compound primary key, as follows:
CREATE TABLE "user_status_updates" (
"username" text,
"id" timeuuid,
"body" text,
PRIMARY KEY ("username", "id")
);
In particular, instead of appending a single column definition with a PRIMARY KEY modi-
fier, we make a separate PRIMARY KEY declaration at the end of the list of columns,
which itself specifies the two columns that make up the compound primary key . While
this is the only way to declare a compound primary key, it's also a perfectly valid way to
declare a single-column primary key. So, our users table from the previous chapter could
have been declared like this:
CREATE TABLE "users" (
"username" text,
"email" text,
"encrypted_password" blob,
PRIMARY KEY ("username")
);
Here, we simply move the PRIMARY KEY declaration to the end of the column list. It's a
little less concise, but it has the exact same effect as a single column definition with a
PRIMARY KEY modifier.