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flattened tables question

Hi!
I have a flattened tables question:
Can I create live aggregate projections on flattened tables ? If I want to groupby or create aggregations on the columns? is it possible somehow?

Thanks!
Keren

Answers

  • And another issue regarding the flattened tables: Can I use the default or SET USING constraint to populate a column that is aggregate function?
    something like -
    CREATE TABLE public.spins_flattened
    (
    ...
    cid int REFERENCES public.spins(id),
    PlayerId_f int DEFAULT (SELECT PlayarId FROM public.spins
    WHERE public.spins(id) = spins_flattened.cid);
    ,
    registered_time timestamp SET USING (
    SELECT min(time) FROM public.spins WHERE (spins.playerId = spins_flattened.PlayerId_f) group by 1 ),
    ...

  • Jim_KnicelyJim_Knicely Administrator
    edited April 13

    Can you cretae a LAP on a Flattened Table? Sure!

    verticademos=> CREATE TABLE dim(c INT);
    CREATE TABLE
    
    verticademos=> CREATE TABLE FACT(c INT SET USING (SELECT c FROM dim));
    CREATE TABLE
    
    verticademos=> CREATE PROJECTION fact_pr AS SELECT c FROM fact;
    CREATE PROJECTION
    
    verticademos=> CREATE PROJECTION fact_lap AS SELECT c, SUM(c) c FROM fact GROUP BY c;
    CREATE PROJECTION
    

    Can I use the default or SET USING / DEFAULT constraint to populate a column that is aggregate function? Sure!

    verticademos=> CREATE TABLE dim (a INT, z INT);
    CREATE TABLE
    
    verticademos=> CREATE TABLE FACT(a INT, c INT DEFAULT (SELECT SUM(z) FROM dim WHERE a = fact.a));
    CREATE TABLE
    
    verticademos=> INSERT INTO dim SELECT 1, 1;
     OUTPUT
    --------
          1
    (1 row)
    
    verticademos=> INSERT INTO dim SELECT 1, 3;
     OUTPUT
    --------
          1
    (1 row)
    
    verticademos=> INSERT INTO fact (a) SELECT 1;
     OUTPUT
    --------
          1
    (1 row)
    
    verticademos=> SELECT * FROM fact;l
     a | c
    ---+---
     1 | 4
    (1 row)
    
    
  • Wow SUPERB!
    Thank!!!!
    And if I want to refresh_columns every 24 hours can I do it automatically somehow through the vertica or do I need a third party app?

  • Jim_KnicelyJim_Knicely Administrator

    Vertica doesn't have a built-in scheduler like that. But you could easily add a SQL command to refresh every 24 hours via crontab.

  • That sounds like a plan
    Many thanks for all your help!
    awesome support !

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