add function to check if table exists in db
add function to check if table exists in db

ubolonton/DDF,ddf-project/DDF,phvu/DDF,ubolonton/DDF,ddf-project/DDF,hsaputra/DDF,phvu/DDF,ddf-project/DDF,ubolonton/DDF,ddf-project/DDF,hsaputra/DDF,ddf-project/ddf-flink,phvu/DDF,milliondreams/ddf-with-flink,hsaputra/DDF,ddf-project/DDF,phvu/DDF,hsaputra/DDF,phvu/DDF,ubolonton/DDF,ubolonton/DDF,ddf-project/ddf-flink,milliondreams/ddf-with-flink,hsaputra/DDF