datasource.hpp

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/* LiteSQL 
 * 
 * The list of contributors at http://litesql.sf.net/ 
 * 
 * See LICENSE for copyright information. */

#ifndef litesql_datasource_hpp
#define litesql_datasource_hpp
#include <set>
#include <string>
#include "litesql/database.hpp"
#include "litesql/selectquery.hpp"
#include "litesql/expr.hpp"
namespace litesql {
using namespace std;
SelectQuery selectObjectQuery(const std::vector<FieldType>& fdatas, 
                               const Expr & e=Expr());
   
template <class T>
SelectQuery selectObjectQuery(const Expr & e=Expr()) {
    std::vector<FieldType> fdatas;
    T::getFieldTypes(fdatas);
    return selectObjectQuery(fdatas, e);
}

template <class T>
class DataSource {
private:
    const Database & db;
    SelectQuery sel;
public:
    DataSource(const Database & db_, const Expr& e = Expr()) 
        : db(db_), sel(selectObjectQuery<T>(e)) {
    }

    DataSource(const Database & db_, const SelectQuery& sel_) 
        : db(db_), sel(sel_) {
    }

    const Database & getDatabase() const {
        return db;
    }

    SelectQuery idQuery() const {
        SelectQuery idq(sel);
        idq.clearResults();
        idq.result(T::Id.fullName());
        return idq;
    }

    size_t count() const {
       SelectQuery cq(sel);
       cq.clearResults();
       cq.limit(0).offset(0);
       cq.result("count(*)");
       return atoi(db.query(cq)[0][0]);
    }

    SelectQuery objectQuery() const {
        return sel;
    }

    Cursor<T> cursor() const {
        return db.template cursor<T>(sel);
    }

    T one() const {
        return *cursor();
    }

    std::vector<T> all() const {
        // \TODO a cursor is not appropriate here, because we fetch all results of the query 
        return cursor().dump();
    }

    DataSource& orderBy(FieldType f, bool asc=true) {
        sel.orderBy(f.fullName(), asc);
        return *this;
    }

    DataSource& orderByRelation(FieldType id, FieldType f, bool asc=true) {
        sel.source(id.table());
        sel.where(id == T::Id);
        sel.orderBy(f.fullName(), asc);
        return *this;
    }
};
 
}
#endif