Method executeImpl

src/Interpreters/InterpreterExistsQuery.cpp:39–101

QueryPipeline InterpreterExistsQuery::executeImpl()
{
    ASTQueryWithTableAndOutput * exists_query = nullptr;
    bool result = false;

    if ((exists_query = query_ptr->as<ASTExistsTableQuery>()))
    {
        if (exists_query->isTemporary())
        {
            result = static_cast<bool>(getContext()->tryResolveStorageID(
                {"", exists_query->getTable()}, Context::ResolveExternal));
        }
        else
        {
            String database = getContext()->resolveDatabase(exists_query->getDatabase());
            getContext()->checkAccess(AccessType::SHOW_TABLES, database, exists_query->getTable());
            result = DatabaseCatalog::instance().isTableExist({database, exists_query->getTable()}, getContext());
        }
    }
    else if ((exists_query = query_ptr->as<ASTExistsViewQuery>()))
    {
        if (exists_query->isTemporary())
        {
            auto storage_id = getContext()->tryResolveStorageID(
                {"", exists_query->getTable()}, Context::ResolveExternal);
            if (storage_id)
            {
                auto table = DatabaseCatalog::instance().tryGetTable(storage_id, getContext());
                result = table && table->isView();
            }
            else
            {
                result = false;
            }
        }
        else
        {
            String database = getContext()->resolveDatabase(exists_query->getDatabase());
            getContext()->checkAccess(AccessType::SHOW_TABLES, database, exists_query->getTable());
            auto table = DatabaseCatalog::instance().tryGetTable({database, exists_query->getTable()}, getContext());
            result = table && table->isView();
        }
    }
    else if ((exists_query = query_ptr->as<ASTExistsDatabaseQuery>()))
    {
        String database = getContext()->resolveDatabase(exists_query->getDatabase());
        getContext()->checkAccess(AccessType::SHOW_DATABASES, database);
        result = DatabaseCatalog::instance().isDatabaseExist(database);
    }
    else if ((exists_query = query_ptr->as<ASTExistsDictionaryQuery>()))
    {
        if (exists_query->isTemporary())
            throw Exception(ErrorCodes::SYNTAX_ERROR, "Temporary dictionaries are not possible.");
        String database = getContext()->resolveDatabase(exists_query->getDatabase());
        getContext()->checkAccess(AccessType::SHOW_DICTIONARIES, database, exists_query->getTable());
        result = DatabaseCatalog::instance().isDictionaryExist({database, exists_query->getTable()});
    }