How to insert/update data in database

Question

I want to save data in a mysql table database using drupal 7 (costume module), but my question is that depends if the value exists I have to use the UPDATE command and if not INSERT command but I don't know how to write this code with the db api.

Answer 1

Use db_merge

In the general sense, a Merge query is a combination of an Insert query and an Update query. If a given condition is met, such as a row with a given primary key already existing, then an Update query is run. If not, an Insert query is run.

Thus, db_merge adds it, if it doesn't exist yet. OR updates it, if it already exists.

db_merge('example')
  ->key(array('name' => $name))
  ->fields(array(
      'field1' => $value1,
      'field2' => $value2,
  ))
  ->execute();

^{by: dzutaro, tlyngej, stewart.adam, AndreyMaximov}