Qx Declarative SQL

Qx features a highly flexible, simple to use, declarative mechanism for querying SQL databases using user structs and other types.

For example, the following SQL table:

person:
    name: VARCHAR
    id: INTEGER

can easily be parsed into a list of C++ data structures like so:

#include <qx/sql/qx-sqldatabase.h>
#include <qx/sql/qx-sqlquery.h>
 
struct person
{
    QString name;
    int id;
 
    QX_SQL_STRUCT(id);
};
 
int main()
{
    Qx::SqlDatabase myDb(u"C:/Some/db.sqlite"_s, "QSQLITE");
    QList<person> allPersons;
 
    Qx::SqlError err =
        myDb.SELECT<person>()
            .FROM<person>()
            .execute(allPersons);
 
    Q_ASSERT(!err.isValid());
 
    ...
}

Likewise, the structure can used in DML queries to add data to a database:

int main()
{
    ...
 
    // Add to DB
    db.INSERT_INTO(person::Sql::_).VALUES<person>()
    ...
}

This system is accessed through the Qx SQL module, predominantly with QX_SQL_STRUCT() et al from qx-sqlquery.h, along with qx-sqlstring.h and qx-sqlinlines.h.

Database access in general is also simplified thanks to Qx::SqlDatabase.

The system still has a ways to go, but is already quite useful for a variety of basic-to-intermediate tasks.

TODO: Make this more complete.