private void createTables(DBCConnector _db)
        {
            var invertedFilesTable = new List <string>();

            invertedFilesTable.Add("File_id VARCHAR(50) NOT NULL");
            invertedFilesTable.Add("Name VARCHAR(50) NOT NULL");
            invertedFilesTable.Add("Author VARCHAR(30)");
            invertedFilesTable.Add("CreationYear INT");
            invertedFilesTable.Add("Path VARCHAR(200) NOT NULL");
            invertedFilesTable.Add("IsAvailable TINYINT(1) NOT NULL");
            invertedFilesTable.Add("PRIMARY KEY (File_id)");
            _db.CreateTable("Files", invertedFilesTable);

            var LookupTermsTable = new List <string>();

            LookupTermsTable.Add("Term_id INT NOT NULL AUTO_INCREMENT");
            LookupTermsTable.Add("Term_txt VARCHAR(30) NOT NULL");
            LookupTermsTable.Add("PRIMARY KEY (Term_id)");
            _db.CreateTable("LookupTerms", LookupTermsTable);

            var PostingFileTable = new List <string>();

            PostingFileTable.Add("Term_id INT NOT NULL AUTO_INCREMENT");
            PostingFileTable.Add("TermName VARCHAR(30) NOT NULL");
            PostingFileTable.Add("File_id  VARCHAR(50) NOT NULL");
            PostingFileTable.Add("Hits INT NOT NULL");
            PostingFileTable.Add("PRIMARY KEY (Term_id , File_id)");
            PostingFileTable.Add("FOREIGN KEY (File_id) REFERENCES Files(File_id)");
            PostingFileTable.Add("FOREIGN KEY (Term_id) REFERENCES LookupTerms(Term_id)");
            _db.CreateTable("PostingFile", PostingFileTable);
        }
 //C'tor
 public DBAccessor()
 {
     _db = new DBCConnector();
     _db.Initialize();
     // createTables(_db); //ONLY at first time
 }