[#430] Add support for the Firebird database - fixed TRUNCATE statement

jOOQ/src/main/java/org/jooq/FactoryOperations.java

@@ -813,6 +813,7 @@ public interface FactoryOperations extends Configuration {
      * supported, it is simulated using an equivalent <code>DELETE</code>
      * statement. This is particularly true for these dialects:
      * <ul>
+     * <li> {@link SQLDialect#FIREBIRD}</li>
      * <li> {@link SQLDialect#INGRES}</li>
      * <li> {@link SQLDialect#SQLITE}</li>
      * </ul>

jOOQ/src/main/java/org/jooq/impl/TruncateImpl.java

@@ -66,6 +66,7 @@ class TruncateImpl<R extends Record> extends AbstractQuery implements Truncate<R
         switch (context.getDialect()) {
 
             // These dialects don't implement the TRUNCATE statement
+            case FIREBIRD:
             case INGRES:
             case SQLITE: {
                 context.sql(create(context).delete(table));