func (np *NaivePlanner) Plan(query parser.Select) []planner.Plan {
result := planner.Plan{}
var last_in_pipeline planner.PlanPipelineComponent
// from
for _, datasource := range query.From {
// look up the data source
ds := datasources.NewDataSourceWithName(datasource.Def)
if ds == nil {
log.Printf("No such datasource exists")
return nil
}
ds.SetName(datasource.Def)
ds.SetAs(datasource.As)
// handle any overs
var lastthis planner.PlanPipelineComponent
lastthis = ds
for _, v := range datasource.Overs {
over := planner.NewOttoOver()
over.SetPath(v.Path)
over.SetAs(v.As)
over.SetSource(lastthis)
lastthis = over
}
if last_in_pipeline != nil {
joiner := planner.NewOttoCartesianProductJoiner()
joiner.SetLeftSource(last_in_pipeline)
joiner.SetRightSource(lastthis)
last_in_pipeline = joiner
} else {
last_in_pipeline = lastthis
}
}
// where
if query.Where != nil {
ottoFilter := planner.NewOttoFilter()
ottoFilter.SetSource(last_in_pipeline)
ottoFilter.SetFilter(query.Where)
last_in_pipeline = ottoFilter
}
if query.IsAggregateQuery {
// in an aggregate query we sometimes need to collect stats
// on fields that we're not aggregating on
// the full list will be the symbols from the SELECT clause
// invalid entries should have been detected earlier
// (columns not in the group by clause and not inside an aggregate function)
stat_fields := make([]string, 0)
if query.Sel != nil {
stat_fields = query.Sel.SymbolsReferenced()
}
// group by
if query.Groupby != nil {
ottoGrouper := planner.NewOttoGrouper()
ottoGrouper.SetGroupByWithStatsFields(query.Groupby, stat_fields)
ottoGrouper.SetSource(last_in_pipeline)
last_in_pipeline = ottoGrouper
} else {
// easy to overlook, but if they use aggregate functions
// this is aggregate query, even though they didnt explicitly
// have a group by clause, we should apply a default group by
// clause that groups everything
ottoGrouper := planner.NewOttoGrouper()
ottoGrouper.SetGroupByWithStatsFields(parser.ExpressionList{parser.NewBoolLiteral(true)}, stat_fields)
ottoGrouper.SetSource(last_in_pipeline)
last_in_pipeline = ottoGrouper
}
// having
if query.Having != nil {
ottoFilter := planner.NewOttoFilter()
ottoFilter.SetSource(last_in_pipeline)
ottoFilter.SetFilter(query.Having)
last_in_pipeline = ottoFilter
}
}
// order by
if query.Orderby != nil {
ottoOrderer := planner.NewOttoOrderer()
ottoOrderer.SetSource(last_in_pipeline)
ottoOrderer.SetOrderBy(query.Orderby)
last_in_pipeline = ottoOrderer
}
// offset
if query.Offset != nil {
offset := planner.NewOttoOffsetter()
offset.SetOffset(query.Offset)
offset.SetSource(last_in_pipeline)
last_in_pipeline = offset
}
// limit
if query.Limit != nil {
limit := planner.NewOttoLimitter()
limit.SetLimit(query.Limit)
limit.SetSource(last_in_pipeline)
last_in_pipeline = limit
}
// select
if query.Sel != nil {
ottoSelecter := planner.NewOttoSelecter()
ottoSelecter.SetSource(last_in_pipeline)
ottoSelecter.SetSelect(query.Sel)
result.Root = ottoSelecter
} else {
defaultSelecter := planner.NewDefaultSelecter()
defaultSelecter.SetSource(last_in_pipeline)
result.Root = defaultSelecter
}
return []planner.Plan{result}
}
