Query an SQLite DB synchronously in C

Question

I am trying to use SQLite in C.

The interface I know exists for querying,

sqlite3_exec

Allows querying data only asynchronously (as far as I found in my searches).

Is there any way to get a result to a "Select count(*) ..." from an SQLite DB synchronously without having to implement something that waits for the data, and returns it to the same function?

I practically want to implement a "howManyItems" method that returns the actual result to its caller...

Thanks.

All SQLite querying functions execute synchronously. Are you sure you are using the official C API and not some wrapper? — Colonel Thirty Two
– Colonel Thirty Two, Commented Sep 20, 2014 at 4:15
I am actually not sure if the run itself is synchronous or asynchronously - but the results are definitely being returned in a callback manner (I will try the suggested solution tomorrow probably) which is out of the scope of the caller, and not how I want to get the results... — evenro
– evenro, Commented Sep 20, 2014 at 21:43
Ah, sqlite3_exec takes a callback that is called with each row. Yes, the sqlite3_prepare functions are what you want. — Colonel Thirty Two
– Colonel Thirty Two, Commented Sep 20, 2014 at 21:47
Thanks.. by the way - is it being run synchronously? just for knowing if my guess was right or wrong.. — evenro
– evenro, Commented Sep 20, 2014 at 21:57

Paul Roub · Accepted Answer · 2014-09-19 20:29:57Z

4

Assuming an open sqlite3 *db, use sqlite3_prepare_v2() and sqlite3_step() (ignoring error checking for brevity):

sqlite3_stmt *statement = null;

// prepare our query
sqlite3_prepare_v2(db, "select count(*) from foo;", -1, &statement, 0);

// if there were parameters to bind, we'd do that here

// retrieve the first row (only row, in this case) of the results
int result = sqlite3_step(statement);

if (result == SQLITE_ROW)
{
  // retrieve the value of the first column (0-based)
  int count = sqlite3_column_int(statement, 0);

  // do something with count
}

// free our statement
sqlite3_finalize(statement);

answered Sep 19, 2014 at 20:29

Paul Roub

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