sqlutil.h

#ifndef SQLUTIL_H
#define SQLUTIL_H

#include <QVariant>
#include <QList>
#include <QSqlDatabase>

class Sql
{
public:
    // SQL keywords
    inline const static QLatin1String as() { return QLatin1String("AS"); }
    inline const static QLatin1String asc() { return QLatin1String("ASC"); }
    inline const static QLatin1String comma() { return QLatin1String(","); }
    inline const static QLatin1String desc() { return QLatin1String("DESC"); }
    inline const static QLatin1String eq() { return QLatin1String("="); }
    // "and" is a C++ keyword
    inline const static QLatin1String et() { return QLatin1String("AND"); }
    inline const static QLatin1String from() { return QLatin1String("FROM"); }
    inline const static QLatin1String fullJoin() { return QLatin1String("FULL JOIN"); }
    inline const static QLatin1String innerJoin() { return QLatin1String("INNER JOIN"); }
    inline const static QLatin1String leftJoin() { return QLatin1String("LEFT JOIN"); }
    inline const static QLatin1String on() { return QLatin1String("ON"); }
    inline const static QLatin1String orderBy() { return QLatin1String("ORDER BY"); }
    inline const static QLatin1String parenClose() { return QLatin1String(")"); }
    inline const static QLatin1String parenOpen() { return QLatin1String("("); }
    inline const static QLatin1String rightJoin() { return QLatin1String("RIGHT JOIN"); }
    inline const static QLatin1String select() { return QLatin1String("SELECT"); }
    inline const static QLatin1String sp() { return QLatin1String(" "); }
    inline const static QLatin1String where() { return QLatin1String("WHERE"); }

    // Build expressions based on key words
    inline const static QString as(const QString &a, const QString &b) { return b.isEmpty() ? a : concat(concat(a, as()), b); }
    inline const static QString asc(const QString &s) { return concat(s, asc()); }
    inline const static QString comma(const QString &a, const QString &b) { return a.isEmpty() ? b : b.isEmpty() ? a : QString(a).append(comma()).append(b); }
    inline const static QString concat(const QString &a, const QString &b) { return a.isEmpty() ? b : b.isEmpty() ? a : QString(a).append(sp()).append(b); }
    inline const static QString desc(const QString &s) { return concat(s, desc()); }
    inline const static QString eq(const QString &a, const QString &b) { return QString(a).append(eq()).append(b); }
    inline const static QString et(const QString &a, const QString &b) { return a.isEmpty() ? b : b.isEmpty() ? a : concat(concat(a, et()), b); }
    inline const static QString from(const QString &s) { return concat(from(), s); }
    inline const static QString fullJoin(const QString &s) { return concat(fullJoin(), s); }
    inline const static QString innerJoin(const QString &s) { return concat(innerJoin(), s); }
    inline const static QString leftJoin(const QString &s) { return concat(leftJoin(), s); }
    inline const static QString on(const QString &s) { return concat(on(), s); }
    inline const static QString orderBy(const QString &s) { return s.isEmpty() ? s : concat(orderBy(), s); }
    inline const static QString paren(const QString &s) { return s.isEmpty() ? s : parenOpen() + s + parenClose(); }
    inline const static QString rightJoin(const QString &s) { return concat(rightJoin(), s); }
    inline const static QString select(const QString &s) { return concat(select(), s); }
    inline const static QString where(const QString &s) { return s.isEmpty() ? s : concat(where(), s); }

    inline const static QString relTablePrefix(int i) { return QString::number(i).prepend(QLatin1String("relTblAl_")); }

    const static QString fullyQualifiedFieldName(const QString &tableName, const QString &fieldName)
    {
        if(tableName.isEmpty())
            return fieldName;

        QString ret;
        ret.reserve(tableName.size() + fieldName.size() + 1);
        ret.append(tableName).append(QLatin1Char('.')).append(fieldName);
        return ret;
    }



    struct Filters{
        Filters() {}
        Filters(QString _fieldText, QVariant _value, char _op)
            :fieldText(_fieldText), value(_value), op(_op) {}

        QString fieldText;
        QVariant value;
        char op;
    };

    enum JoinMode
    {
        InnerJoin,
        LeftJoin,
        RightJoin,
        FullJoin
    };

    static void addGlobalFilter(const QString &fieldText, const QVariant &value, char op = '%')
    {
        m_filters.append(Filters(fieldText, value, op));
    }


    static QString getGlobalFilter(const QString &table, QSqlDatabase db);

    static QString getLikeTables(const QString &table1, const QString &table2,
                                 const QString &qualif1, const QString &qualif2, QSqlDatabase db);

    static QString getJoinTables(const QString &table1, const QString &table2,
                                 const QString &qualif1, const QString &qualif2,
                                 const QString &field1, const QString &field2,
                                 JoinMode joinMode = InnerJoin, QSqlDatabase db = QSqlDatabase());

    static QList<Filters> m_filters;
};

#endif // SQLUTIL_H