I use MySQL connector by Dr. Bell and after some time it stops. PLEASE HELP

Dear gentlemen of the Arduino forum I hope you can help me with this problem

I am using an arduino atmega2560, a wifi shield and a dust sensor (dsm501a) for a project. I have to translate the measurements of my sensor to a mysql data base. I used the mySQL connector created by Dr. Charles Bell. When I see that the blue DATA led of the wifi shield blinks it is because the data is being translated from the sensor to the mySQL data base. Everything is working fine but suddenly at one point (sometimes 1 hour, sometimes 30 minutes) it stops blinking, my serial monitor paralyzes and no more data is transmitted. Could you please help me? What do I have to do? Do I need to add something in my code? This system is supposed to work 24 hours and the whole time saving the measurements from the sensor therefore it cannot stop. I attach my code so it is easy for you making any comment.
Please I hope you can help me.
Best regards,
Sebastian Silva P.

dsm501a.ino (10.8 KB)

cesarproano and I are the same person, I have two arduino accounts one for my university and the other personal. So I hope seeing me writing here don't confuse you.
Regards,
Cesar Sebastian Silva P.

Do yourself a huge favor. Quit using Strings. They fragment memory.

I'd seriously consider much shorter table and column names, too.

I'd also seriously consider using the F() macro to keep useless data out of SRAM.
Serial.println(F("Welcome to dsm501a project"));

      Vout1LowRatio = float((float(counterVout1LowYP)/20)*100); //otherwise the result is an int

Once you cast counterVout1LowYP to a float, the result of the arithmetic is a float. There is not reason to do another cast.

Hi Paul thank you so much for your recommendations. I am gonna take them into consideration. One question if I don't use Strings, so what should i use?
About this problem that I have told you that at one point it stops working what should i do?
Best regards,
And thanks again for your time
Sebastian

if I don't use Strings, so what should i use?

char arrays, NULL terminated - aka strings.