How to append bindings to fill holes?

[werto87]

In this example all holes get filled at once:

string firstName = "John", lastName = "Smith";
int personId = 7;

sql << "insert into person(id, firstname, lastname) values(:id, :fn, :ln)",
        use(personId), use(firstName), use(lastName);

I want to append the "use" step by step.
Something like this:

string firstName = "John", lastName = "Smith";
int personId = 7;

MyStatement myStatement{};
myStatement.query= "insert into person(id, firstname, lastname) values(:id, :fn, :ln)";
myStatement.appendUse(personId);
myStatement.appendUse(firstName);
myStatement.appendUse(lastName);
myStatement.execute (true);

Details
I am writing convince functions which are build on soci and boost::fusion.
For example "insertStruct" to add one row into the EasyClass table.

   insertStruct (sql, EasyClass{ "222", "someValue" });

Creating the sql expresion is done by iterating over the members of EasyClass.
So for "insertStruct (sql, EasyClass{ "222", "someValue" });" the sql is:

INSERT INTO EasyClass(playerId,points) VALUES('222','someValue')

This allows sql injections. So I want to use "use()" instead of copying the values of the struct into VALUES().
Is it possible to create the query with holes and fill them by appending?

[vadz]

You do it like this:

    soci::statement st(session);
    st.alloc();
    st.prepare("insert into ...");

    st.exchange(use(value1));
    st.exchange(use(value2));
    st.exchange(use(value3));

    st.define_and_bind();
    st.execute();

[werto87]

I checked your suggestion and it works for me. Thank You!