C++ wrapper class SQLite advice - c++

Question

I'm learning C++ and have a question about classes and wrappers. I'm writing an application for a raspberry pi. I have a class called SensorClass whose methods read data from various sensors attached to the board.
class SensorClass {
public:
SensorClass();
virtual ~SensorClass();
int getTemperature();
int getPressue();
;
I want to write the data to a local sqlite database when it is read. On the SQLite website there are a number of wrapper classes.
SQLite wrappers
I'm wondering if I should use one of these to for example insert data into the database when it has been read.
I'm thinking then I would be separating the code and just calling for example the SQLite insert method in the getTemperature() function. Would this be a good idea? Which wrapper should I use?
Example SQlite wrapper class
Alternatively I could hard code the database operations in the getTemperature() method like this.
int SensorClass::getTemperature(){
// read temperature
//insert into database
/* Create SQL statement */
sql = "INSERT INTO DATAPOINTS (Temperature) " \
"VALUES (15); " \
/* Execute SQL statement */
rc = sqlite3_exec(db, sql, callback, 0, &zErrMsg);
}
Thanks for your advice

Answer 1

It would generally be better to separate the two things. i.e. make the sensor class do the job on sensing stuff well and only that.
Then have a separate class that does the job of logging sensor data to the database well. You may find it is better to insert entire rows into the database in one go. And you may also decide that you want to only log data periodically at a fixed sampling rate.
Then in your main application loop / via an event driven timer, you can do measurements and record data as separate steps.
e.g.
void APP_tick(void)
{
SensorValues values = sensors.readValues();
logger.writeValues(values);
}
By separating responsibility, you can then change the logger class out easily - you may end up deciding that you don't want to use a database and would rather just log the data into flat files in order to use less disk space and improve performance.
If using SQLite then you might find it worthwhile using prepared statements to avoid having to compile the SQL query every time you execute it (which is expensive in CPU terms and you are running this on a fairly limited system).