public String buildSearchString(String metr, String cont, String popu, 
				boolean greater, boolean exact) {
			String qString = "SELECT * FROM " + dbase_name + " WHERE ";
			
			ArrayList<String> queries = new ArrayList<String>();
			if (!metr.equals("")) {
				String str = "";
				if (exact) {
					str += "metropolis = \"" + metr + "\" ";
				}else {
					str += "metropolis LIKE \"" + "%" + metr + "%" + "\" ";
				}				
				queries.add(str);
			}
			
			if (!cont.equals("")) {
				String str = "";
				if (exact) {
					str += " continent = \"" + cont + "\" ";
				} else {
					str += " continent LIKE \"" + "%" + cont + "%" + "\" ";
				}
				queries.add(str);
			}
			
			if (!popu.equals("")) {
				String str = "population ";
				if (greater) {
					str += "> ";
				}else {
					str += "< " + popu + " OR " + "population = ";
				}
				str += popu;
				queries.add(str);
			}
			
			boolean first = true;
			for (int i = 0; i < queries.size(); i++) {
				if (!first) qString += " AND ";
				qString += queries.get(i);
				first = false;
			}
			
			qString += ";";
			
			return qString;
		}