qx::QxSoftDelete : soft delete (or logical delete) behavior to update a row into database (flag it as deleted) instead of delete it from database More...

#include <QxSoftDelete.h>

Public Types
enum	mode { mode_flag, mode_date_time }
Public Member Functions
	QxSoftDelete ()
	QxSoftDelete (const QString &sColumn)
	QxSoftDelete (const QString &sColumn, mode eMode)
	~QxSoftDelete ()
QString	getTableName () const
QString	getColumnName () const
QString	getSqlQueryToFetch () const
QString	getSqlQueryToUpdate () const
QString	getSqlQueryToCreateTable () const
mode	getMode () const
bool	getSqlFetchInJoin () const
void	setTableName (const QString &sTable)
void	setColumnName (const QString &sColumn)
void	setSqlQueryToFetch (const QString &s)
void	setSqlQueryToUpdate (const QString &s)
void	setSqlQueryToCreateTable (const QString &s)
void	setMode (mode eMode)
void	setSqlFetchInJoin (bool b)
bool	isEmpty () const
QString	buildSqlTablePointName (const QString &sTable=QString()) const
QString	buildSqlQueryToFetch (const QString &sTable=QString()) const
QString	buildSqlQueryToUpdate () const
QString	buildSqlQueryToCreateTable () const
Private Attributes
QString	m_sTable
	Table name where soft delete behavior is applied.
QString	m_sColumn
	Column name to store soft delete information.
QString	m_sSqlQueryToFetch
	Overrided user SQL query to fetch an item, if empty QxOrm library builds a default SQL query.
QString	m_sSqlQueryToUpdate
	Overrided user SQL query to update an item, if empty QxOrm library builds a default SQL query.
QString	m_sSqlQueryToCreateTable
	Overrided user SQL query to create table, if empty QxOrm library builds a default SQL query.
mode	m_eMode
	Soft delete mode : 'mode_flag' with a boolean column, 'mode_date_time' with a date-time column containing deletion date-time.
bool	m_bFetchInJoin
	Add SQL condition to fetch in the JOIN part (default value), for backward compatibility with previous versions of QxOrm library set this value to false (means fetch in the WHERE part)

Detailed Description

qx::QxSoftDelete : soft delete (or logical delete) behavior to update a row into database (flag it as deleted) instead of delete it from database

A soft delete doesn't remove rows from database (this is not a physical delete) : a new column is added to the table definition to flag a row as deleted or not. This column can contain a boolean (1 means row deleted, 0 or NULL means row not deleted), or can contain deletion date-time (if empty or NULL, row is not deleted). So you can reactivate a deleted row by setting NULL or empty value into database.

To define a soft delete behavior with QxOrm library, you have to use the class qx::QxSoftDelete in function mapping by class qx::register_class<T>. Here is an example with the class Bar containing 2 properties m_id and m_desc :

namespace qx {
template <> void register_class(QxClass<Bar> & t)
{
   t.setSoftDelete(qx::QxSoftDelete("deleted_at"));

   t.id(& Bar::m_id, "id");
   t.data(& Bar::m_desc, "desc");
}}

SQL queries builded by QxOrm library will take into account this soft delete parameter to add conditions (don't fetch deleted item, don't delete physically a row, etc.). For example, if you execute this code with the class Bar :

Bar_ptr pBar; pBar.reset(new Bar());
pBar->setId(5);
QSqlError daoError = qx::dao::delete_by_id(pBar);     qAssert(! daoError.isValid());
qx_bool bDaoExist = qx::dao::exist(pBar);             qAssert(! bDaoExist);
daoError = qx::dao::delete_all<Bar>();                qAssert(! daoError.isValid());
long lBarCount = qx::dao::count<Bar>();               qAssert(lBarCount == 0);
daoError = qx::dao::destroy_all<Bar>();               qAssert(! daoError.isValid());

You will obtain following output trace :

[QxOrm] sql query (93 ms) : UPDATE Bar SET deleted_at = '20110617115148615' WHERE id = :id
[QxOrm] sql query (0 ms) : SELECT Bar.id AS Bar_id_0, Bar.deleted_at FROM Bar WHERE Bar.id = :id AND (Bar.deleted_at IS NULL OR Bar.deleted_at = '')
[QxOrm] sql query (78 ms) : UPDATE Bar SET deleted_at = '20110617115148724'
[QxOrm] sql query (0 ms) : SELECT COUNT(*) FROM Bar WHERE (Bar.deleted_at IS NULL OR Bar.deleted_at = '')
[QxOrm] sql query (110 ms) : DELETE FROM Bar

Note : To delete physically a row from database, you have to use followings functions : qx::dao::destroy_by_id() and qx::dao::destroy_all().

Other note : it is recommended to define into database an index on column deleted_at to optimize execution of SQL queries.

Definition at line 96 of file QxSoftDelete.h.

Member Enumeration Documentation

enum qx::QxSoftDelete::mode

Enumerator:

mode_flag
mode_date_time

Definition at line 101 of file QxSoftDelete.h.

Constructor & Destructor Documentation

qx::QxSoftDelete::QxSoftDelete ( )

qx::QxSoftDelete::QxSoftDelete ( const QString & sColumn )

qx::QxSoftDelete::QxSoftDelete	(	const QString &	sColumn,
		mode	eMode
	)

qx::QxSoftDelete::~QxSoftDelete ( )

Member Function Documentation

QString qx::QxSoftDelete::buildSqlQueryToCreateTable ( ) const

QString qx::QxSoftDelete::buildSqlQueryToFetch ( const QString & sTable = QString() ) const

QString qx::QxSoftDelete::buildSqlQueryToUpdate ( ) const

QString qx::QxSoftDelete::buildSqlTablePointName ( const QString & sTable = QString() ) const

QString qx::QxSoftDelete::getColumnName ( ) const

mode qx::QxSoftDelete::getMode ( ) const

bool qx::QxSoftDelete::getSqlFetchInJoin ( ) const

QString qx::QxSoftDelete::getSqlQueryToCreateTable ( ) const

QString qx::QxSoftDelete::getSqlQueryToFetch ( ) const

QString qx::QxSoftDelete::getSqlQueryToUpdate ( ) const

QString qx::QxSoftDelete::getTableName ( ) const

bool qx::QxSoftDelete::isEmpty ( ) const

void qx::QxSoftDelete::setColumnName ( const QString & sColumn )

void qx::QxSoftDelete::setMode ( mode eMode )

void qx::QxSoftDelete::setSqlFetchInJoin ( bool b )

void qx::QxSoftDelete::setSqlQueryToCreateTable ( const QString & s )

void qx::QxSoftDelete::setSqlQueryToFetch ( const QString & s )

void qx::QxSoftDelete::setSqlQueryToUpdate ( const QString & s )

void qx::QxSoftDelete::setTableName ( const QString & sTable )

Member Data Documentation

bool qx::QxSoftDelete::m_bFetchInJoin [private]

Add SQL condition to fetch in the JOIN part (default value), for backward compatibility with previous versions of QxOrm library set this value to false (means fetch in the WHERE part)

Definition at line 111 of file QxSoftDelete.h.

mode qx::QxSoftDelete::m_eMode [private]

Soft delete mode : 'mode_flag' with a boolean column, 'mode_date_time' with a date-time column containing deletion date-time.

Definition at line 110 of file QxSoftDelete.h.

QString qx::QxSoftDelete::m_sColumn [private]

Column name to store soft delete information.

Definition at line 106 of file QxSoftDelete.h.

QString qx::QxSoftDelete::m_sSqlQueryToCreateTable [private]

Overrided user SQL query to create table, if empty QxOrm library builds a default SQL query.

Definition at line 109 of file QxSoftDelete.h.

QString qx::QxSoftDelete::m_sSqlQueryToFetch [private]

Overrided user SQL query to fetch an item, if empty QxOrm library builds a default SQL query.