Database: academic
Question: return me the author who has the most number of papers containing keyword " Relational Database " .
SQL: select t2.name from publication_keyword as t5 join keyword as t1 on t5.kid  =  t1.kid join publication as t3 on t3.pid  =  t5.pid join writes as t4 on t4.pid  =  t3.pid join author as t2 on t4.aid  =  t2.aid where t1.keyword  =  "relational database" group by t2.name order by count ( distinct t3.title ) desc limit 1;