Info API::CreateIndex(SqlCommandCreateIndex* command){
IndexManager index_manager;
CatalogManager catalog_manager;
RecordManager record_manager;
std::string index_name = command->index_name();
std::string attribute_name = command->column_name();
std::string table_name = command->table_name();
if (catalog_manager.HasIndex(index_name)){
std::string error_info;
error_info = "Index \"" + index_name + "\" already exists.";
return Info(error_info);
}
if (!catalog_manager.HasTable(table_name)){
std::string error_info;
error_info = "table \"" + table_name + "\" not exists.";
return Info(error_info);
}
TableInfo table = catalog_manager.GetTableInfo(table_name);
if(!table.HasAttribute(attribute_name)){
std::string error_info;
error_info = "attribute \"" + attribute_name + "\" not exists.";
return Info(error_info);
}
if (!table.attribute(attribute_name).is_unique() && !table.attribute(attribute_name).is_primary_key()){
std::string error_info;
error_info = "attribute \"" + attribute_name + "\" is not an unique attribute.";
return Info(error_info);
}
else{
IndexInfo index_info(index_name, table_name, attribute_name);
//create index in index manager
if(index_manager.CreateIndex(table.attribute(attribute_name).type(),table.attribute(attribute_name).length(), index_info)){
auto all_records = record_manager.SelectAllRecords(table);
for (auto record : all_records){
if(!index_manager.AddRecord(table,index_info,record.first.at(table.attribute_index(index_info.attribute_name())),record.second)){
return Info("Update index failed.");
}
}
if (!catalog_manager.RegisterIndex(index_info))
{
return Info("Register Index failed.");
}
//update table info in catalog manager
table.add_index(attribute_name, index_name);
catalog_manager.WriteTableInfo(table);
return Info();
}
else{
return Info("Create index failed.");
}
}
}
