Function main

examples/sqlite_ex.cpp:33–133

// ----------------------------------------------------------------------------------------

int main() try
{
    // Open the SQLite database in the stuff.db file (or create an empty database in
    // stuff.db if it doesn't exist).
    database db("stuff.db");

    // Create a people table that records a person's name, age, and their "data".
    if (!table_exists(db,"people"))
        db.exec("create table people (name, age, data)");


    // Now let's add some data to this table.  We can do this by making a statement object
    // as shown.  Here we use the special ? character to indicate bindable arguments and
    // below we will use st.bind() statements to populate those fields with values.  
    statement st(db, "insert into people VALUES(?,?,?)");

    // The data for Davis
    string name = "Davis";
    int age = 32;
    matrix<double> m = randm(3,3); // some random "data" for Davis

    // You can bind any of the built in scalar types (e.g. int, float) or std::string and
    // they will go into the table as the appropriate SQL types (e.g. INT, TEXT).  If you
    // try to bind any other object it will be saved as a binary blob if the type has an
    // appropriate void serialize(const T&, std::ostream&) function defined for it.  The
    // matrix has such a serialize function (as do most dlib types) so the bind below saves
    // the matrix as a binary blob.
    st.bind(1, name);
    st.bind(2, age);
    st.bind(3, m); 
    st.exec(); // execute the SQL statement.  This does the insert.


    // We can reuse the statement to add more data to the database.  In fact, if you have a
    // bunch of statements to execute it is fastest if you reuse them in this manner. 
    name = "John";
    age = 82;
    m = randm(2,3); 
    st.bind(1, name);
    st.bind(2, age);
    st.bind(3, m); 
    st.exec();
    


    // Now lets print out all the rows in the people table.
    statement st2(db, "select * from people");
    st2.exec();
    // Loop over all the rows obtained by executing the statement with .exec().
    while(st2.move_next())
    {
        string name;
        int age;
        matrix<double> m;
        // Analogously to bind, we can grab the columns straight into C++ types.  Here the
        // matrix is automatically deserialized by calling its deserialize() routine.
        st2.get_column(0, name);
        st2.get_column(1, age);