title: PostgreSQL for update statement
body: <p>PostgreSQL has read committed isolation level. Now I have a transaction which consists of a single DELETE statement and this delete statement has a subquery consisting of a SELECT statement for selection the rows to delete.</p>
  
  <p>Is it true that I have to use FOR UPDATE in the select statement to get no conflicts with other transaction? </p>
  
  <p>My thinking is the following: First the corresponding rows are read out from the table and in a second step these rows are deleted, so another transaction could interfere.</p>
  
  <p>And what about a simple DELETE FROM myTable WHERE id = 4 statement? Do I also have to use FOR UPDATE?</p>