sqlite3_exec() Callback function clarification

Question

I am having trouble understanding the use of the callback function in a SQLite3 database.

I understand it is used to traverse SELECT statements with multiple records.

Answer 1

That tutorial is horrible, because it does not use anything but sqlite3_exec().

In the general case, the only useful way to use sqlite3_exec() is to replace it with sqlite3_prepare_v2()/sqlite3_step()/sqlite3_column_*()/sqlite3_finalize() calls so that you can read the data in the same place where you actually need to handle it:

sqlite3_stmt *stmt;
const char *sql = "SELECT ID, Name FROM User";
int rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
if (rc != SQLITE_OK) {
    print("error: ", sqlite3_errmsg(db));
    return;
}
while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
    int id           = sqlite3_column_int (stmt, 0);
    const char *name = sqlite3_column_text(stmt, 1);
    // ...
}
if (rc != SQLITE_DONE) {
    print("error: ", sqlite3_errmsg(db));
}
sqlite3_finalize(stmt);