After creating cubes, measures, and dimensions, you map the dimensions and . schema following the instructions in Installing the Oracle OLAP 11g Sample. I realize you asked this in August , but in case it still helps you or others, as of Feb , SQL Developer has an OLAP extension which seems to be what. In this course, students learn to progressively build an OLAP data model to support Students learn to design OLAP cubes to serve as a summary management.
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Query Rewrite allows SQL queries that are requesting aggregate data from a detailed fact table to be automatically re-directed by the Oracle Database optimizer to access a suitable summary table in the database instead.
Sign up using Facebook. Dimension must have one or more levels so that rules out parent-child dimensions then Cube must be compressed why? Although “cost-based” aggregation is good, IMHO it could be made even better if another two options, “size-based” aggregation and “time-based” aggregation were added. Regular relational table based MVs have been available in Oracle Database since Oracle 8, and are widely used by BI systems as they simplify the summary management aspects of those systems, and also deliver a feature called query re-write which can improve query performance.
Looking through buildding online help, you can see that if you partition the cube, you can set different percentages for the levels at or below the selected partitioning level of the cube, and the levels above, which is interesting as in the 10g version of Oracle OLAP, you couldn’t preaggregate levels above the partitioning level the “capstone level” – this was the reason cubess you didn’t partition at too low a level in your cube – most of the cube then would need to have it’s aggregates calculated on the fly.
The values that are buildign be contained in the dimensions are loaded in a later process, together with the links between dimension members that are loaded into the relation object. So, looks like this script is useful to run. Select a cube in the navigation tree.
Oracle OLAP: Creating Cubes with Simple SQL
It is only available with Oracle Enterprise Edition. That’s pretty good actually. For example, to create a product dimension, you’d first create the table that contains the data, and then create the dimension afterwards. It’s not helping me much.
For the time being though, it does make this unnecessary join to the dimension tables to retrieve the dimension data, although from other tests I’ve done on larger data sets, this is still faster than accessing relational summaries. Feel free to ask questions on our Oracle forum. Let’s look at a scenario. The objective is to create a cube and cube-organized materialized view that manages all summary data beginning at Month, Item, City and Channel levels.
This process started with the acquisition of Express from IRI inwith technical integration starting with Oracle Database 9i. More usually, Analytic Workspaces and their multidimensional objects – dimensions, hierarchies, measures and calculations etc – are created, populated, refreshed and maintained by one or more of the tools that Oracle provides:.
The dimension itself looks fine: This time, I create the cube again, select the same options, press the Apply button on the cube dialog, and it creates the materialized view for me.
I have an Oracle 10g Database with relational tables in it. Thus, Excel loap a client to the cubes. I’m not sure on what basis it picked the “Quarter” level, except perhaps that it’s the middle one between month and year, but I press cancel for the moment and go back to the advisor, this time picking the Statistics option instead.
Refreshing the OLAP cube can be plugged into exactly 1g same MV refresh mechanisms used for regular relational MVs, so the cubes can easily slot into existing maintenance procedures. I was especially interested to note a “wait events” script as well – I don’t know whether this had anything to do with it, but I suggested this to the product management team a similar time ago, I’ll be interested to see what activities and waits this provides diagnostics on.
The amount of code, and its complexity will be much less than if the same thing is attempted without OLAP.
First of all though, I xubes down all the constraints that already exist in the source schema, and run the script generated by the Materialized View advisor to make sure everything’s cubws up just right for query rewrite.
Analytic Workspaces are multidimensional workspaces held within LOBs in Oracle tables, that store data using a technology originally introduced with Oracle’s Express line of products. A variable is like a fact table with one fact column, and is defined thus:.
The first product of that category long before the term “OLAP” was coined in the ‘s was an early iteration of what was to dubes Oracle Express. I want to create dimensions and cubes from that data. There is a temptation to add more an more MVs to the system as new slow running queries are identified. Analytic Workspace Manager checks the cube for the prerequisites for adding materialized view capabilities. So what we’ve shown here is several things.
Also, a single Cube will deliver aggregate data equivivalent to all the possible summary combinations that exist along the hierarchies of the dimensions over that original leaf level fact buildong.
I choose the Time Dimension option, whereapon the disk whirs a bit and comes up with the following recommendation: It combines first class multidimensional data types, and calculation engine with the other performance, scalability, security, high availability and manageability features of Oracle Database. I am VERY confused about all of the documentation. Now this looks like a very neat new feature. My guess here is that, in this initial release, it it does’t actually support fast-refresh materialized views, certainly selecting this option makes the MV unavailable – I expect this will become available as a feature in a later patch release.
If you look underneath the calculation, there’s an expression displayed that corresponds to the calculation I’ve just defined: Also, unlike relational OLAP cubes, multidimensional OLAP Option cubes are usually “fully solved,” with all aggregations computed at load time, giving a faster, more predictable response time for users’ queries.
A First Look at Oracle OLAP 11g
Going back then to the original question, first of all, if you’re creating relational OLAP dimensions and cubes, you don’t need to create additional tables to hold your biilding, as your dimensions and cubes are just additional metadata that sits on top of existing tables that is later used by either the query rewrite mechanism, the summary advisor, or by OLAP tools that use the Java OLAP API.
This must be like the old Sparsity Advisor in 10gR2, which actually samples the source data and calculates the actual sparsity value for each dimension. Next, we need to create some dimensions. Personal tools Not logged in Talk Contributions.
In particular I’m trying to find out whether it runs ok without any show-stopper bugs, whether there are any new features in Analytic Workspace Manager, how well the Materialized View integration works, whether it’s any faster to query than previous releases, and – and this is the killer question, the thing that I’m most interested in – is it a viable way to speed up slow-running relational Discoverer reports?
Once we have created our dimension objects, we next create a variable to hold our transactional data. Complete buildinf Materialized View tab. To create your first analytic workspace, type in. I especially like the New Load Step feature, this makes it very clear whether the cube olp incrementally loaded or synchronized deleting old data out of the cube was always a headache in previous AWM versions, and most new developers didn’t realize this didn’t happen by default and it strikes me that this is a very nice, very welcome new bit of functionality.
The rules sub-tab has the same features as previous AWM versions cubse the aggregation order and methodhowever the new precompute tab now offers the ability to precompute by levels, klap per previous AWM versions, or by percentage of the cube, which is new.
To create materialized views: