QH::PKG::DBObject Class Reference

The DBObject class- main class for work with data base. More...

#include <dbobject.h>

Inheritance diagram for QH::PKG::DBObject:

Collaboration diagram for QH::PKG::DBObject:

Public Member Functions
	DBObject ()
	~DBObject () override
bool	isValid () const override
	isValid This method check current object to valid.
bool	isHaveAPrimaryKey () const
	isHaveAPrimaryKey This method return true if this object has a primary key. If you want to cache this database object then primary key must be not null.
virtual void	clear ()
	clear This method clear all data of database object. Override This method for remove or reset your own members of class.
virtual DBObject *	createDBObject () const =0
	createDBObject This method should be create a object with the some type as the object called this method. Example of override:
virtual PrepareResult	prepareSelectQuery (QSqlQuery &q) const
	prepareSelectQuery This method should be prepare a query for selected data. Override this method for get item from database. The default implementation generate default select:
virtual bool	fromSqlRecord (const QSqlRecord &q)=0
	fromSqlRecord This method should be initialize this object from the executed sqlRecord. The Default implementation get general dbObject information ( id and table name ). Override This method for initialize this object from sql query.
virtual PrepareResult	prepareInsertQuery (QSqlQuery &q, bool replace) const
	prepareInsertQuery This method should be prepare a query for insert object into database. You need to create a own insert sql query for this object into database. Override this method for insert item into database. By Default This method prepare a insert query using the data that returned from the variantMap method.
virtual PrepareResult	prepareUpdateQuery (QSqlQuery &q) const
	prepareUpdateQuery this method should be prepare a insert data query.
virtual PrepareResult	prepareRemoveQuery (QSqlQuery &q) const
	prepareRemoveQuery This method should be prepare a query for remove this object from a database. Override this method for remove this item from database. The default implementation remove item from id or primaryKey for more information see DBObject::condition method.
virtual bool	isCached () const
	isCached This method sholud be return status of object. If this method return true then this object can be saved into cache of database. Override this method and set this value to false for composite objects (objects for which a select query can return several objects or an object that does not have a direct representation in the database but contains common characteristics of several objects).
virtual bool	isBundle () const
	isBundle This method definef determines whether the object will be abstract (composite objects) or single object If this function return true then SqlDBWriter create only one object after invoked selectquery. And if the selectquery function return a list of more 1 elements then a method fromSqlRecord must be invoked for each all elements of list.
DbAddress	dbAddress () const
	dbAddress This method return address of the database object. IF the object is not valid then this method return an invalid database address.
QString	toString () const override
virtual DBVariantMap	variantMap () const
	variantMap This method should be create a DBVariantMap implementation of this database object.
virtual QString	table () const =0
	table This method should be return name of the database table that should be contains objects with this type.
Public Member Functions inherited from QH::PKG::AbstractData
	~AbstractData () override
virtual unsigned short	cmd () const =0
	cmd - This is command of this object, (for generate cmd use macross QH_PACKAGE)
virtual QString	cmdString () const =0
	cmdString - This is command string of this object, (for generate cmd use macross QH_PACKAGE)
virtual bool	toPackage (Package &package, const DistVersion &reqVersion, unsigned int triggerHash=0) const
	toPackage This method convert this class object to the package. For more info see Package class.
QString	toString () const override
	toString - Return a string implementation for this object.
template<class C , class... Args>
C *	create (Args &&... args) const
	create - This is factory method for create a new object.
void	fromPakcage (const Package &pkg)
	fromPakcage - This method initialize the current object from a package class object.
Public Member Functions inherited from QH::StreamBase
	StreamBase ()
virtual	~StreamBase ()
bool	fromBytes (const QByteArray &data)
	fromBytes This method provide initialization of object from byte array.
QByteArray	toBytes () const
	toBytes This method convert a current object to bytes array.
bool	fromBase64 (const QString &data)
	fromBase64 This method provide initialization of object from the base64 string.
bool	fromBase64 (const QByteArray &data)
	fromBase64 This method provide initialization of object from the base64 string.
QByteArray	toBase64 () const
	toBase64 This method convert a current object to the base64 string.
template<class T >
T &	copy (const StreamBase &right)
	copy This is base copy method for all StreamBase structures. Default implementation it is copy from byteArray.
template<class T >
bool	compare (const T &right)
	compare This method compare array signatures of this and right objects.

Protected Member Functions
QDataStream &	fromStream (QDataStream &stream) override
	fromStream This method should be read all bytes from the stream object and full the current object.
QDataStream &	toStream (QDataStream &stream) const override
	fromStream This method should be write all members of the current object to the stream object.
virtual std::pair< QString, QMap< QString, QVariant > >	condition () const
	condition This method must to return a condition of the WHERE block of the sql query. This method using on default implementation of DBObject::prepareSelectQuery and DBObject::prepareRemoveQuery methods. The default implementation generate when block by map for more information see the variantMap nethod. Override this method for customize your select or delete query.
virtual QString	primaryKey () const
	primaryKey This method must be return the name of primary key of this object table. If you want to create data object without primary key just return empty string.
virtual QVariant	primaryValue () const
	primaryValue This method is wraper of DBAddress::id. If This object do not contains a id value then return invalid value.
bool	isInsertPrimaryKey () const
	isInsertPrimaryKey This method check primaryKeys type. If the primary key have a type MemberType::Insert then return true.
Protected Member Functions inherited from QH::PKG::AbstractData
	AbstractData ()
	AbstractData - Base constructor of this object.
Protected Member Functions inherited from QH::StreamBase
virtual int	parsingVersion () const
	parsingVersion this method return parsing version of Qt. By Default is 0 (last available parsing). see https://doc.qt.io/qt-6/qdatastream.html#Version-enum
virtual unsigned int	typeId () const
	typeId This method return id of type.

Additional Inherited Members
Static Public Member Functions inherited from QH::PKG::AbstractData
static unsigned int	command ()
	command This static method that return glaball code of this object.
static QString	commandText ()
	commandText This method return text of package command

Detailed Description

The DBObject class- main class for work with data base.

Note

If you set in the default constructor primaryKey to empty value. The your object disable cache support. For more information see the DBObject::isCached method.

Warning

Object with empty table name is invalid.

See also

DataBaseNode

Definition at line 93 of file dbobject.h.

Constructor & Destructor Documentation

DBObject()

QH::PKG::DBObject::DBObject

(

)

Definition at line 22 of file dbobject.cpp.

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~DBObject()

QH::PKG::DBObject::~DBObject ( )

override

Definition at line 26 of file dbobject.cpp.

Member Function Documentation

clear()

void QH::PKG::DBObject::clear ( )

virtual

clear This method clear all data of database object. Override This method for remove or reset your own members of class.

Note

The Default implementation do nothing

Reimplemented in QH::PKG::DBObjectsRequest< T >.

Definition at line 318 of file dbobject.cpp.

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condition()

std::pair< QString, QMap< QString, QVariant > > QH::PKG::DBObject::condition ( ) const

protectedvirtual

condition This method must to return a condition of the WHERE block of the sql query. This method using on default implementation of DBObject::prepareSelectQuery and DBObject::prepareRemoveQuery methods. The default implementation generate when block by map for more information see the variantMap nethod. Override this method for customize your select or delete query.

Returns

condition string and qvariant map of the values for binding (bindingKey:bindValue).

Note

This operation can not be block the sql request. Use the QString or int type for values of condition. If you want to bytes array in condition then override the DBObject::condition method.

Example of overriding:

QString DBObject::condition() const {
    return {{"id = :id"},
            {{{":id"}, {getId()}}}};
}

Reimplemented in QH::PKG::DBObjectsRequest< T >.

Definition at line 212 of file dbobject.cpp.

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createDBObject()

virtual DBObject * QH::PKG::DBObject::createDBObject ( ) const

pure virtual

createDBObject This method should be create a object with the some type as the object called this method. Example of override:

return create<MyClassName>();

Note

The object created on this method not destroyed automatically.

Returns

pointer of new object with the same type.

Implemented in QH::PKG::DBObjectsRequest< T >, QH::PKG::DeleteObject, QH::PKG::GetMaxIntegerId, QH::PKG::GetSingleValue, and QH::PKG::SetSingleValue.

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dbAddress()

DbAddress QH::PKG::DBObject::dbAddress

(

)

const

dbAddress This method return address of the database object. IF the object is not valid then this method return an invalid database address.

Returns

The database address of current object.

Definition at line 242 of file dbobject.cpp.

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fromSqlRecord()

virtual bool QH::PKG::DBObject::fromSqlRecord ( const QSqlRecord &  q )

pure virtual

fromSqlRecord This method should be initialize this object from the executed sqlRecord. The Default implementation get general dbObject information ( id and table name ). Override This method for initialize this object from sql query.

Note

This method will be invoke for one object. But if isBundle return 'true' then a function fromSqlRecord moust be invoked for each all elements of list.

Parameters

q	This is query object.

Returns

true if method finished successful.

Exampel of override fromSqlRecord method:

bool ExampleObject::fromSqlRecord(const QSqlRecord &q) {
 
    id = q.value("id").toInt();
    exampleMember = q.value("exampleMember").toInt();
    return isValid();
}

Implemented in QH::PKG::DBObjectsRequest< T >, QH::PKG::DeleteObject, QH::PKG::GetMaxIntegerId, QH::PKG::GetSingleValue, and QH::PKG::SetSingleValue.

fromStream()

QDataStream & QH::PKG::DBObject::fromStream ( QDataStream &  stream )

overrideprotectedvirtual

fromStream This method should be read all bytes from the stream object and full the current object.

Note

The implementation of this method should be invoke a method of base class.

Parameters

stream

This is Qt stream object.

Returns

Qt stream object.

Examle of base simple implementation:

QDataStream &ExampleClass::fromStream(QDataStream &stream) const {
    StreamBase::toStream(stream);
    stream >> exampleMember;
    return stream;
}

Implements QH::StreamBase.

Reimplemented in QH::PKG::DBObjectsRequest< T >, QH::PKG::DBObjectsRequestWithStream< T >, and QH::PKG::DeleteObject.

Definition at line 251 of file dbobject.cpp.

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isBundle()

bool QH::PKG::DBObject::isBundle ( ) const

virtual

isBundle This method definef determines whether the object will be abstract (composite objects) or single object If this function return true then SqlDBWriter create only one object after invoked selectquery. And if the selectquery function return a list of more 1 elements then a method fromSqlRecord must be invoked for each all elements of list.

Returns

true if the object is a selection from a set of database object.

Reimplemented in QH::PKG::DBObjectSet.

Definition at line 208 of file dbobject.cpp.

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isCached()

bool QH::PKG::DBObject::isCached ( ) const

virtual

isCached This method sholud be return status of object. If this method return true then this object can be saved into cache of database. Override this method and set this value to false for composite objects (objects for which a select query can return several objects or an object that does not have a direct representation in the database but contains common characteristics of several objects).

Returns

True if item in cache. The Default implementation check the primary key if this object and if primary key is valid then return true else return false.

Reimplemented in QH::PKG::DeleteObject, QH::PKG::GetMaxIntegerId, QH::PKG::GetSingleValue, QH::PKG::SetSingleValue, and QH::PKG::DBObjectSet.

Definition at line 200 of file dbobject.cpp.

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isHaveAPrimaryKey()

bool QH::PKG::DBObject::isHaveAPrimaryKey

(

)

const

isHaveAPrimaryKey This method return true if this object has a primary key. If you want to cache this database object then primary key must be not null.

Returns

true if object has a primary key.

Definition at line 314 of file dbobject.cpp.

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isInsertPrimaryKey()

bool QH::PKG::DBObject::isInsertPrimaryKey ( ) const

protected

isInsertPrimaryKey This method check primaryKeys type. If the primary key have a type MemberType::Insert then return true.

Returns

true if the primary key have the MemberType::Insert type.

Definition at line 238 of file dbobject.cpp.

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isValid()

bool QH::PKG::DBObject::isValid ( ) const

overridevirtual

isValid This method check current object to valid.

Returns

True if class isValid.

Reimplemented from QH::PKG::AbstractData.

Reimplemented in QH::PKG::DBObjectsRequest< T >.

Definition at line 303 of file dbobject.cpp.

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prepareInsertQuery()

PrepareResult QH::PKG::DBObject::prepareInsertQuery ( QSqlQuery &  q, bool  replace  ) const

virtual

prepareInsertQuery This method should be prepare a query for insert object into database. You need to create a own insert sql query for this object into database. Override this method for insert item into database. By Default This method prepare a insert query using the data that returned from the variantMap method.

Parameters

q	Thuis is query object.
replace	This option disable or enable replacing of exists objects.

Default insert query have a next template:

INSERT INTO %0(%1) VALUES (%3)

For more information see the DBObject::variantMap method.

Note

before creating a own object you need to create a own database structure.

Parameters

q	This is query object.

Returns

PrepareResult object with information about prepare results.

Example of overriding:

PrepareResult ExampleObject::prepareInsertQuery(QSqlQuery &q, replace) const {
 
    DBVariantMap map = variantMap();
 
 
    QString queryString = "INSERT INTO %0(%1) VALUES (%2) ";
 
 
    queryString = queryString.arg(table());
    QString tableInsertHeader = "";
    QString tableInsertValues = "";
 
    for (auto it = map.begin(); it != map.end(); ++it) {
 
        tableInsertHeader += it.key();
        tableInsertValues += ":" + it.key();
 
        if (it + 1 != map.end()) {
            tableInsertHeader += ", ";
            tableInsertValues += ", ";
        }
 
    }
 
    queryString = queryString.arg(tableInsertHeader);
    queryString = queryString.arg(tableInsertValues);
 
    if (q.prepare(queryString)) {
 
        for (auto it = map.begin(); it != map.end(); ++it) {
            q.bindValue(":" + it.key(), it.value().value);
        }
 
        return PrepareResult::Success;
    }
 
    return PrepareResult::Fail;
}

Note

If you want disable this method, just override it and return the PrepareResult::Disabled value.

Reimplemented in QH::PKG::SetSingleValue, and QH::PKG::DBObjectSet.

Definition at line 61 of file dbobject.cpp.

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prepareRemoveQuery()

PrepareResult QH::PKG::DBObject::prepareRemoveQuery ( QSqlQuery &  q ) const

virtual

prepareRemoveQuery This method should be prepare a query for remove this object from a database. Override this method for remove this item from database. The default implementation remove item from id or primaryKey for more information see DBObject::condition method.

Parameters

q	This is query object.

Returns

PrepareResult object with information about prepare results.

Note

If you want disable this method just override it and return the PrepareResult::Disabled value.

Reimplemented in QH::PKG::DBObjectSet.

Definition at line 267 of file dbobject.cpp.

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prepareSelectQuery()

PrepareResult QH::PKG::DBObject::prepareSelectQuery ( QSqlQuery &  q ) const

virtual

prepareSelectQuery This method should be prepare a query for selected data. Override this method for get item from database. The default implementation generate default select:

"select * from [table] where id=[id]".

This method create where block using the condition method. See DBObject::condition fr more information.

Parameters

q	This is query object.

Returns

PrepareResult object with information about prepare results.

Note

If you want disable this mehod just override it and return the PrepareResult::Disabled value.

Reimplemented in QH::PKG::GetMaxIntegerId, QH::PKG::GetSingleValue, and QH::PKG::DBObjectSet.

Definition at line 30 of file dbobject.cpp.

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prepareUpdateQuery()

PrepareResult QH::PKG::DBObject::prepareUpdateQuery ( QSqlQuery &  q ) const

virtual

prepareUpdateQuery this method should be prepare a insert data query.

Bt Default This method generate query like this:

UPDATE value SET value = 2 WHERE id = 1

If you want to create a own insert query override this method.

Example of overriding this method:

PrepareResult prepareUpdateQuery(QSqlQuery& q) const {
    DBVariantMap map = variantMap();
 
    QString queryString = "UPDATE %0 SET %1 WHERE %2";
 
    queryString = queryString.arg(table());
    QString tableUpdateValues = "";
    QString tableUpdateRules = QString("%0 = :%0").
            arg(primaryKey());
 
    for (auto it = map.begin(); it != map.end(); ++it) {
        if (!(it.value().type & MemberType::Update)) {
            continue;
        }
 
        if (tableUpdateValues.size()) {
            tableUpdateValues += ", ";
        }
 
        tableUpdateValues += QString("%0= :%0").arg(it.key());
 
    }
 
    queryString = queryString.arg(tableUpdateValues);
    queryString = queryString.arg(tableUpdateRules);
 
    if (q.prepare(queryString)) {
 
        for (auto it = map.begin(); it != map.end(); ++it) {
            if (it.value().type != MemberType::InsertUpdate) {
                continue;
            }
 
            q.bindValue(":" + it.key(), it.value().value);
        }
 
        return PrepareResult::Success;
    }
 
    return PrepareResult::Fail;
}

Parameters

q	This is query object.

Returns

PrepareResult object with information about prepare results.

Reimplemented in QH::PKG::SetSingleValue, and QH::PKG::DBObjectSet.

Definition at line 123 of file dbobject.cpp.

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primaryKey()

QString QH::PKG::DBObject::primaryKey ( ) const

protectedvirtual

primaryKey This method must be return the name of primary key of this object table. If you want to create data object without primary key just return empty string.

Note

If you returned empty value then this method can not be prepare insert update and delete querys.

Returns

The primary key name.

Reimplemented in QH::PKG::DBObjectSet, QH::PKG::DeleteObject, QH::PKG::GetSingleValue, and QH::PKG::SetSingleValue.

Definition at line 230 of file dbobject.cpp.

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primaryValue()

QVariant QH::PKG::DBObject::primaryValue ( ) const

protectedvirtual

primaryValue This method is wraper of DBAddress::id. If This object do not contains a id value then return invalid value.

Returns

Value of primaryKey ( database id ).

Note

If you alredy override the condition method then You can return empty string because this method using in generate default condition only.

See also

DBObject::condition.

Reimplemented in QH::PKG::DeleteObject, QH::PKG::GetSingleValue, and QH::PKG::SetSingleValue.

Definition at line 234 of file dbobject.cpp.

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table()

virtual QString QH::PKG::DBObject::table ( ) const

pure virtual

table This method should be return name of the database table that should be contains objects with this type.

Returns

table name that contains object with this type.

Implemented in QH::PKG::DBObjectSet, QH::PKG::DeleteObject, QH::PKG::GetMaxIntegerId, QH::PKG::GetSingleValue, and QH::PKG::SetSingleValue.

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toStream()

QDataStream & QH::PKG::DBObject::toStream ( QDataStream &  stream ) const

overrideprotectedvirtual

fromStream This method should be write all members of the current object to the stream object.

Note

The implementation of this method should be invoke a method of base class.

Parameters

stream

This is Qt stream object.

Returns

Qt stream object.

Examle of base simple implementation:

QDataStream &ExampleClass::toStream(QDataStream &stream) const {
    StreamBase::toStream(stream);
    stream << exampleMember;
    return stream;
}

Implements QH::StreamBase.

Reimplemented in QH::PKG::DBObjectsRequest< T >, QH::PKG::DBObjectsRequestWithStream< T >, and QH::PKG::DeleteObject.

Definition at line 259 of file dbobject.cpp.

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toString()

QString QH::PKG::DBObject::toString ( ) const

override

Definition at line 246 of file dbobject.cpp.

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variantMap()

DBVariantMap QH::PKG::DBObject::variantMap ( ) const

virtual

variantMap This method should be create a DBVariantMap implementation of this database object.

IF you have the database field with autoincrement you need to remove MemberType::Insert attribute from the your key. For more information see the MemberType::PrimaryKeyAutoIncrement attribute.

Example of return value:

return {{"name",        {"Andrei",      MemberType::Insert}},
        {"age",         {26,            MemberType::InsertUpdate}},
        {"extraData",   {QByteArray{},  MemberType::InsertUpdate}}};

Example of override:

auto map = ParrentClass::variantMap();
map.insert("myNewMembers", {_newMember.toBytes(), MemberType::InsertUpdate});
return map;

Note

This method using for create a default sql save request see the DBObject::prepareSaveQuery method for more information.

Returns

the QVariantMap implementation of this database object.

Note

If you want disable this functionality then override this method and return an empty map. But do not forget override the DBObject::prepareSelectQuery method, because its default implementation return error message.

Reimplemented in QH::PKG::DBObjectsRequest< T >, and QH::PKG::DeleteObject.

Definition at line 295 of file dbobject.cpp.

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---

The documentation for this class was generated from the following files:

• src/public/packages/dbobject.h
• src/public/packages/dbobject.cpp