title: When should I use transactions in my queries?
body: <p>I'm reading very detailed tutorials on how to use transactions with database types and database engines, but I haven't found a guide that teaches me when and why I should use them.</p>
  
  <p>I know transactions are usually used for banking, so when we work with money data, but I can imagine they are used in many other ways.</p>
  
  <p>Today I'm working on a page with various <code>INSERT</code> statements for a relational database, and I wanted to know if this is one of the cases when I should use them.</p>
  
  <p>I get an impression that I don't know the cases when the data can be partially lost (apart from coder errors) so I'm always worried about when I should use them.</p>
  
  <p>Can someone explain or give some link with these fundamental rules?</p>
  
  <p>I'm using <code>MySQL 5.0.8</code>. Should I use <code>InnoDB</code> for all tables that need transactions? If yes, is <code>InnoDB</code> slower than the common <code>MyISAM</code> but I shouldn't worry about that?</p>
  
  <p>thanks</p>