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#include "queryexecutorreplaceviews.h"
#include "parser/ast/sqlitecreateview.h"
#include "parser/ast/sqliteselect.h"
#include "schemaresolver.h"
#include <QDebug>
QueryExecutorReplaceViews::~QueryExecutorReplaceViews()
{
if (schemaResolver)
{
delete schemaResolver;
schemaResolver = nullptr;
}
}
bool QueryExecutorReplaceViews::exec()
{
SqliteSelectPtr select = getSelect();
if (!select || select->explain)
return true;
if (select->coreSelects.size() > 1)
return true;
if (select->coreSelects.first()->distinctKw)
return true;
replaceViews(select.data());
select->rebuildTokens();
updateQueries();
return true;
}
void QueryExecutorReplaceViews::init()
{
if (!schemaResolver)
schemaResolver = new SchemaResolver(db);
}
QStringList QueryExecutorReplaceViews::getViews(const QString& database)
{
QString dbName = database.isNull() ? "main" : database.toLower();
if (views.contains(dbName))
return views[dbName];
views[dbName] = schemaResolver->getViews(database);
return views[dbName];
}
SqliteCreateViewPtr QueryExecutorReplaceViews::getView(const QString& database, const QString& viewName)
{
View view(database, viewName);
if (viewStatements.contains(view))
return viewStatements[view];
SqliteQueryPtr query = schemaResolver->getParsedObject(database, viewName, SchemaResolver::VIEW);
if (!query)
return SqliteCreateViewPtr();
SqliteCreateViewPtr viewPtr = query.dynamicCast<SqliteCreateView>();
if (!viewPtr)
return SqliteCreateViewPtr();
viewStatements[view] = viewPtr;
return viewPtr;
}
void QueryExecutorReplaceViews::replaceViews(SqliteSelect* select)
{
SqliteSelect::Core* core = select->coreSelects.first();
QList<SqliteSelect::Core::SingleSource*> sources = core->getAllTypedStatements<SqliteSelect::Core::SingleSource>();
typedef QPair<SqliteSelect::Core::SingleSource*, SqliteCreateViewPtr> SourceViewPair;
SqliteCreateViewPtr view;
QList<SourceViewPair> sourceViewPairs;
for (SqliteSelect::Core::SingleSource* src : sources)
{
if (src->table.isNull())
continue;
QStringList viewsInDatabase = getViews(src->database);
if (!viewsInDatabase.contains(src->table, Qt::CaseInsensitive))
continue;
view = getView(src->database, src->table);
if (!view)
{
qWarning() << "Object" << src->database << "." << src->table
<< "was identified to be a view, but could not get it's parsed representation.";
continue;
}
if (usesAnyView(view->select, viewsInDatabase))
{
// Multi-level views (view selecting from view, selecting from view...).
// Such constructs build up easily to huge, non-optimized queries.
// For performance reasons, we won't expand such views.
qDebug() << "Multi-level views. Skipping view expanding feature of query executor. Some columns won't be editable due to that.";
return;
}
sourceViewPairs << SourceViewPair(src, view);
}
for (SourceViewPair& pair : sourceViewPairs)
{
view = pair.second;
QString alias = pair.first->alias.isNull() ? view->view : pair.first->alias;
QString sql = view->equivalentSelectTokens().detokenize();
Parser parser;
if (!parser.parse(sql) || parser.getQueries().size() == 0)
qWarning() << "Couldn't replace view " << view->view << " by equivalent select " << sql;
else
{
pair.first->select = new SqliteSelect(*dynamic_cast<SqliteSelect *>(parser.getQueries().first().get()));
pair.first->alias = alias;
pair.first->database = QString();
pair.first->table = QString();
// replaceViews(pair.first->select); // No recursion, as we avoid multi-level expanding.
}
}
context->viewsExpanded = true;
}
bool QueryExecutorReplaceViews::usesAnyView(SqliteSelect* select, const QStringList& viewsInDatabase)
{
for (SqliteSelect::Core*& core : select->coreSelects)
{
QList<SqliteSelect::Core::SingleSource*> sources = core->getAllTypedStatements<SqliteSelect::Core::SingleSource>();
for (SqliteSelect::Core::SingleSource* src : sources)
{
if (src->table.isNull())
continue;
if (viewsInDatabase.contains(src->table, Qt::CaseInsensitive))
return true;
}
}
return false;
}
uint qHash(const QueryExecutorReplaceViews::View& view)
{
return qHash(view.database + "." + view.view);
}
QueryExecutorReplaceViews::View::View(const QString& database, const QString& view) :
database(database), view(view)
{
}
int QueryExecutorReplaceViews::View::operator==(const QueryExecutorReplaceViews::View& other) const
{
return database == other.database && view == other.view;
}
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