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koffice/kexi/kexidb/drivers/sqlite/sqlitealter.cpp

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/* This file is part of the KDE project
Copyright (C) 2006 Jaroslaw Staniek <js@iidea.pl>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this program; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
// ** bits of SQLiteConnection related to table altering **
#include "sqliteconnection.h"
#include <kexidb/utils.h>
#include <kstaticdeleter.h>
#include <tqmap.h>
using namespace KexiDB;
enum SQLiteTypeAffinity { //as defined here: 2.1 Determination Of Column Affinity (http://sqlite.org/datatype3.html)
NoAffinity = 0, IntAffinity = 1, TextAffinity = 2, BLOBAffinity = 3
};
//! helper for affinityForType()
static KStaticDeleter< TQMap<int,int> > KexiDB_SQLite_affinityForType_deleter;
TQMap<int,int> *KexiDB_SQLite_affinityForType = 0;
//! \return SQLite type affinity for \a type
//! See doc/dev/alter_table_type_conversions.ods, page 2 for more info
static SQLiteTypeAffinity affinityForType(Field::Type type)
{
if (!KexiDB_SQLite_affinityForType) {
KexiDB_SQLite_affinityForType_deleter.setObject( KexiDB_SQLite_affinityForType, new TQMap<int,int>() );
KexiDB_SQLite_affinityForType->insert(Field::Byte, IntAffinity);
KexiDB_SQLite_affinityForType->insert(Field::ShortInteger, IntAffinity);
KexiDB_SQLite_affinityForType->insert(Field::Integer, IntAffinity);
KexiDB_SQLite_affinityForType->insert(Field::BigInteger, IntAffinity);
KexiDB_SQLite_affinityForType->insert(Field::Boolean, IntAffinity);
KexiDB_SQLite_affinityForType->insert(Field::Date, TextAffinity);
KexiDB_SQLite_affinityForType->insert(Field::DateTime, TextAffinity);
KexiDB_SQLite_affinityForType->insert(Field::Time, TextAffinity);
KexiDB_SQLite_affinityForType->insert(Field::Float, IntAffinity);
KexiDB_SQLite_affinityForType->insert(Field::Double, IntAffinity);
KexiDB_SQLite_affinityForType->insert(Field::Text, TextAffinity);
KexiDB_SQLite_affinityForType->insert(Field::LongText, TextAffinity);
KexiDB_SQLite_affinityForType->insert(Field::BLOB, BLOBAffinity);
}
return static_cast<SQLiteTypeAffinity>((*KexiDB_SQLite_affinityForType)[(int)type]);
}
tristate SQLiteConnection::drv_changeFieldProperty(TableSchema &table, Field& field,
const TQString& propertyName, const TQVariant& value)
{
/* if (propertyName=="name") {
}*/
if (propertyName=="type") {
bool ok;
Field::Type type = KexiDB::intToFieldType( value.toUInt(&ok) );
if (!ok || Field::InvalidType == type) {
//! @todo msg
return false;
}
return changeFieldType(table, field, type);
}
// not found
return cancelled;
}
/*!
From http://sqlite.org/datatype3.html :
Version 3 enhances provides the ability to store integer and real numbers in a more compact
format and the capability to store BLOB data.
Each value stored in an SQLite database (or manipulated by the database engine) has one
of the following storage classes:
* NULL. The value is a NULL value.
* INTEGER. The value is a signed integer, stored in 1, 2, 3, 4, 6, or 8 bytes depending
on the magnitude of the value.
* REAL. The value is a floating point value, stored as an 8-byte IEEE floating point number.
* TEXT. The value is a text string, stored using the database encoding (UTF-8, UTF-16BE or UTF-16-LE).
* BLOB. The value is a blob of data, stored exactly as it was input.
Column Affinity
In SQLite version 3, the type of a value is associated with the value itself,
not with the column or variable in which the value is stored.
.The type affinity of a column is the recommended type for data stored in that column.
See alter_table_type_conversions.ods for details.
*/
tristate SQLiteConnection::changeFieldType(TableSchema &table, Field& field,
Field::Type type)
{
Q_UNUSED(table);
const Field::Type oldType = field.type();
const SQLiteTypeAffinity oldAffinity = affinityForType(oldType);
const SQLiteTypeAffinity newAffinity = affinityForType(type);
if (oldAffinity!=newAffinity) {
//type affinity will be changed
}
return cancelled;
}