Hiperspace.SQL 1.0.2

Hiperspace.SQL

Hiperspace.SQL is a full SQL query engine for Hiperspace, supporting the full range of joins, aggregations, and subqueries.

Hiperspace.SQL provides the same query functionality as a .NET client can use with LINQ queries, but without the need to write code in C#/F#

Hiperspace fully supports point-in-time "time travel" queries that are not possible with Python Data-Frames or DuckDB

Features

• Hiperspace.SQL is not limited to queries of columns within a table, but supports the full navigation of properties of Hiperspace elements
• Where a column is a complex object it is returned as a JSON object
• Executing a batch of SQL statements return columnar data frames (dictionary of column-name and array of values)
• Explain SQL returns the execution plan, detailing the SetSPaces accessed and keys used for search (Key, Index, Scan)
• The Parquet method returns a Parquet file that can be used with any Apache Parquet library, or added to DuckDB OLAP store

Data Dictionary

SCHEMA_TABLE

SCHEMA_COLUMN

SCHEMA_PROPERTY

Examples

Simple query

SELECT p.Name, p.Gender FROM Persons as p WHERE p.Name = 'Lucy'

Query parameters

SELECT p.Name, p.Gender FROM Persons as p WHERE p.Name = :name

Query batches

SELECT p.Name, p.Gender FROM Persons as p WHERE p.Name = :name;
SELECT Name as name, Father as father from   Persons ;

Joins

SELECT  p.Name, f.Name as Father, f.Father as GrandFather
FROM    Persons as p 
join    Persons as f on p.Father.Name = f.Name
WHERE   p.Name = :name

Aggregates

select  p.Father.Name, count(p.Name) as Children
from    Persons as p
group by p.Father.Name as f
having count(*) > 1;

Like expressions

select  p.Father.Name, count(p.Name) as Children
from    Persons as p
where   Name like 'L%' and Name like '%y' or (Name like '%u%' and Name like '_uc_')
group by p.Father.Name as f
having count(*) > 1;

Null handling

select  p.Name, p.Father.Name
from    Persons as p
where   Name is not null

in query

SELECT p.Name, p.Gender 
FROM Persons as p 
WHERE p.Gender in (select p2.Gender from Persons as p2 where p2.Name = 'Lucy')

union

SELECT p.Name, p.Gender 
FROM Persons as p 
WHERE p.Name in ('Lucy', 'Mark')
union 
SELECT p.Name, p.Gender 
FROM Persons as p 
WHERE p.Name in ('Eve', 'Mary')

inline view

SELECT p.Name, p.Gender 
FROM Persons as p 
join (select p2.Gender from Persons as p2 where p2.Name = 'Lucy') as p3 on p.Gender = p3.Gender

dictionary query

select * from SCHEMA_TABLES;
select * from SCHEMA_COLUMNS;
select * from SCHEMA_PROPERTIES;

API

The Hiperspace.SQL API can be called from any language that supports DOTNET interop, including Python (using pythonnet). Access via the Hiperspace.SQL.Engine object that is constructed with a reference to any domain space.

Explain

Provides a detailed breakdown of the query execution plan

member engine.Explain (source, parameters : IDictionary<string,obj>) : string array = 

Execute

Executes the SQL queries and returns an array of Data Frames

member engine.Execute (source , parameters : IDictionary<string,obj>) : IDictionary<string, obj array> array  =

Parquet

Executes the SQL queries will a n array of filenames (one for each statement) and returns the filenames after writing the results to the Apache Parquet files.

member this.Parquet (source, fileNames, parameters : IDictionary<string,obj>): string array =