Fragmented and Aggregated tables in OBIEE using ODI Part 4/5: Populating the Aggregated tables


Hey guys, how are you?

Continuing the series Fragmented and Aggregated tables in OBIEE using ODI and today we are talking about how to Populating the Aggregated tables using ODI.

Just to make easier for you to navigate in this series, here’s the parts of it:

Creating the tables: I’ll explain the advantages and how you can create the fragmented tables and also how to further improve performance using partitioning and sub partitioning.

Managing the partitions of the Fragmented/Aggregated tables: Here you’ll see how to manage all partitions using ODI.

Populating the Fragmented tables using ODI: Here you’ll find how to create generic components to load all fragmented tables we need to.

Populating the Aggregated tables using ODI: Here you’ll find how to create generic components to load all Aggregated tables we need to.

Setting the OBIEE Repository: Finally, we’ll going to setting up the OBIEE repository to make use of all tables.

Today we are in the final step before we can work in our OBIEE repository to put all these 18 fact tables together. The data load for our Aggregated tables.

The aggregation in fact is a very simple process, we just need to remove all detailed columns we have in the detail fact table and leave just the ID’s columns. After that we just need to reduce the level of the ID of the column we want to aggregate and sum all the data at that new level.

In our case we going to use the PERIOD_ID to do that, because period is the most common choice when we talk about aggregated table and serve well in most of the cases.

And that’s why I design the PERIOD_ID as YYYYQMMDD, because is very simple and easy to manipulate this number to go up or down a period, as well to do range or even transform it back to date. It’s way easier than create a surrogate key or whatever, even if you want to work with SCD.

As you probably already guest by now, we’ll use the command on source and command on target again to do the aggregations, this way we can have only one code to spread the data through out aggregate fact tables.

In the command on source for the monthly level table, we just need a query in the source that return the name of the detailed table plus the name of the monthly table. Since I designed all tables with a specific name pattern, we can easily manipulate the table name to get the month table from the detail table like this:

We don’t need anything fancy here because in the last post we create a proc to call six time the same scenario passing different parameter to it.

One of these parameter is the name of the fact table it needs to be loaded and this information is store in the variable #JAT_TABLE_NAME (already replaced by the value in the picture) and what I have done there is just split the table name using REGEXP to get the forth and the fifth occurrences of ‘_’ and concatenate everything back adding a _M_ in the middle of it, creating my Monthly level fact table name.

With data we have the detail table name that the scenario needs to load and also the monthly level fact table name that we need to use for that loop. We just need to create a query to aggregate the data, what’s very straight forward.

As the query will change depending of the design of the table, this one is just intended for explain what needs to be done since the idea is very simple. First we replace the name of the table that  we wish to insert data and the table that we wish to get the data from for our to variables: #JAT_TABLE_NAME that we are sending when we call this scenario and #JAT_M_TABLE_NAME that we just create in the Command on Source tab.

With this, for each loop, the scenario will get the data from the right source table and will insert in the right aggregated table. Now we need to aggregate the data, also a very simple matter. All we need to do is to join the detailed fact table with the period dimension and, because this is a range partition, we need to get the first date of that month and the last date of that month, that’s why we have that MIN and MAX filtered by the Year and Month.

With the right data filtered, we just need to aggregate the data and use the FISCAL_MONTH_ID instead of the PERIOD_ID, this way the data will be aggregated by month. And we are done here.

By the way, we could instead of using the between to get the right range of the partition filtered the partition itself using explicit partition filtering:

This will make oracle to go straight to that partition. The only thing is that you need to pass the partition name, that in our case is very straight forward, specially because we are creating and managing the partitions ourselves. We could have oracle create the partitions automatically using INTERVAL (for another post) but if we do that oracle will also create the names of partitions like SYS###### and that will make everything harder to filter by partitions. Anyway, this is just another option we can have.

For the quarter level it’s even easier because we don’t need to worry about range partitions anymore. We just need to have our Command on Source return the Monthly level table name and our Quarterly level table name:

As you can see, the query is the same, the only difference is that we insert a ‘_Q_’ in the middle of our string. And for the insert in the Target Command tab we just need, as before, replace the tables using the right variable in each case, join with the DIM_PERIOD_MONTH to have the right level of data, filter the Monthly level table using any method and then use the QUARTER_ID to sum the Monthly level data to the Quarterly level data and that’s it.

That’s all we need to do to populate all aggregated table. And we finally have all data populated in our tables and now we can start to create the OBIEE repository. It’s wort to mentioning that if you resume everything that I said until this point, we basically had to:

  • Create our tables;
  • Create one procedure to:
    • Create the partitions;
    • Truncate the partitions before we load data;
    • Call and loop the scenario that will load data;
    • Drop the old partitions
  • Create another procedure to:
    • Load detail data;
    • Load Monthly level data;
    • Load Quarterly level data;

What this means is that with just two procedure we can maintain and populate a very complex environment in a very clean way with very little points of failures.

This is a very elegant approach and as I always said, if is too complex and/or difficult, you were doing something wrong. It is just a meter of think about the design first, all that needs to be done, and split it in a logical and reusable way. If you do that, everything will be simple to be archived using ODI.

I hope this series has been useful so far and I see you in the last chapter.

4 Responses to “Fragmented and Aggregated tables in OBIEE using ODI Part 4/5: Populating the Aggregated tables”

  1. […] Populating the Aggregated tables using ODI: Here you’ll find how to create generic components to l… […]

  2. […] Populating the Aggregated tables using ODI: Here you’ll find how to create generic components to l… […]

  3. […] Populating the Aggregated tables using ODI: Here you’ll find how to create generic components to l… […]

  4. […] For a better EPM world « Fragmented and Aggregated tables in OBIEE using ODI Part 4/5: Populating the Aggregated tables […]

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