The nocreatedbifnotexists filter removes statements that start with:

CREATE DATABASE IF NOT EXISTS

This can be useful in heterogeneous replication where Tungsten Replicator specific databases need to be removed from the replication stream.

The filter works in two phases. The first phase creates a global variable within the prepare() function that defines the string to be examined:

function prepare()
{
  beginning = "CREATE DATABASE IF NOT EXISTS";
}

Row based changes can be ignored, but for statement based events, the SQL is examine and the statement removed if the SQL starts with the text in the beginning variable:

sql = d.getQuery();
if(sql.startsWith(beginning))
{
    data.remove(i);
    i--;
}