How can I identify for which core release a database is?

Question

I have been sent site files and a database for a website to review but have had trouble loading it up. The core and contributed modules are all D7, but when I import the database and run a page on the browser I get a message,

PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'example.semaphore' doesn't exist: SELECT expire, value FROM {semaphore} WHERE name = :name; Array ( [:name] => variable_init ) in lock_may_be_available() (line 167 of example.com/includes/lock.inc).

I suspect this means that the database I have been given is a D6 one, but need to confirm this. Is the version declared anywhere, or is the absence of the semaphore the evidence I need?

Answer 1

In Drupal 6 the node revisions are in {node_revisions}, and in Drupal 7 the node revisions are in {node_revision}. So, you can just check which table exists. There are some structural differences with the tables, too. For example there is a status column in D7, but not in D6.