What is the best way to have full text search where data in database is frequently updated
I presume that update frequency in the worst case, would be a day, in your case. You could try Sphinx for this, as it is really fast and works well with MySql. And you could think of ElasticSearch also if the data is huge.

https://stackoverflow.com/questions/2271600/elasticsearch-sphinx-lucene-solr-xapian-which-fits-for-which-usage