Get operator

[hadrienk]

Dataset ds_o := get(PersistentDataset ds_id {, PersistentDataset ds_id}\* {,keep(keepPart Component {, keepClause Component})} {,filter(Component filterPart)}
{,aggregate(
[sum|avg|median|count|count_distinct|min|max]({include NULLS} MeasureComponent aggrPart) {,[sum|avg|median|count|count_distinct|min|max]({include NULLS} MeasureComponent aggrPart)}
)} )

• Update grammar tests
• Update grammar
• Refine Connector interface
• Test that the input datasets ds_id must have the same Logical Data Structure, which is the same Components in number, name and type (static).
• Test that keepPart must be a Component expression containing exactly the name of a Component of any ds (complex Component expressions, combining more than one Component are not allowed) (static).
• Test that aggrPart must be a Component expression containing exactly the name of a MeasureComponent present in any ds (no complex Component expressions, combining more than one Component is allowed). If there is at least one aggrPart, there must be one for each MeasureComponent that is present in a keepPart. If keepPart is omitted, all MeasureComponents must be in the aggregate. This means that there cannot be MeasureComponents, kept that are not used in aggregations (static).