4. The method of claim 3 , further comprising: identifying operators of the database query language statement having a cost above a threshold cost; for each costly operator, examining the one or more annotations associated with the identified operator; and generating a structural recommendation about the costly operator to improve the database query language statement.
4. The method of claim 3 , further comprising: identifying operators of the database query language statement having a cost above a threshold cost; for each costly operator, examining the one or more annotations associated with the identified operator; and generating a structural recommendation about the costly operator to improve the database query language statement. 5. The method of claim 4 , wherein generating the structural recommendation comprising: retrieving an alternative operator from the one or more annotations; comparing a cost of the alternative operator with a cost of the costly operator; and mapping the recommendation to use the alternative operator to the costly operator in the database query language statement.