1. Physical Layer of a Repository

2. March 6, 2009 Agenda – What is a Repository? –What is meant by Physical Layer? –Data Source, Connection Pool, Tables and Columns –Steps to Build a Physical Layer Define System Data Source Name (DSN) for data sources Test connectivity to data sources Import data source schemas Edit connection pool properties Define physical keys and join conditions if they were not imported

3. March 6, 2009 Physical Layer Represents the physical structure of the data sources to which the Oracle BI Server submits queries Is the metadata that describes the source of the analytical data Defines what the data is, how the data relates, and how to access the data Is used by the OBI Server to generate SQL to access the business data to provide answers to business questions. Is created using the Analytics Administration Tool –Can be imported from the source information Is typically the first layer built in the repository

4. March 6, 2009 Physical Layer Continued

5. March 6, 2009 Data Sources OBI Server can access data stored in: –Normalized schema databases –Star or snowflake schema databases –Flat files –Spreadsheets –XML –And so on

6. March 6, 2009 Data Sources Continued Connectivity is established to the data source via: –An ODBC Data Source (generic) driver –Native drivers for Oracle and DB2 Data source to access an Oracle database

7. March 6, 2009 Connection Pool Specifies the ODBC or native data source name Defines how the OBI Server connects to the data source Allows multiple users to share a pool of database connections –May create multiple connection pools to improve performance for groups of users ODBC Data Source name

8. March 6, 2009 Connection Pool continued The Connection Pool is an object in the Physical layer that describes access to the data source. It contains information about the connection b/w the OBI Server & the data source. We can configure multiple concurrent data source requests (queries) to share a single database connection reducing the overhead of connection to a database. For each connection pool,we must specify the maximum number of concurrent connections allowed. After this limit is reached, the Analytics Server routes all other connection requests to another connection pool,or if no other pool exists,the connection request waits until a connection becomes available. Increasing the allowed number of concurrent connections can potentially increase the load on the underlying database accessed by the connection pool. Test & Consult with your DBA to make sure the data source can handle the number of connections specified in the connection pool.

9. March 6, 2009 Tables and Columns Represent the physical structure of the data –Import only the tables and columns needed for analytical processing Table Columns

10. March 6, 2009 Key Columns Primary Key –Uniquely identifies a single row of data –Comprised of a column or set of columns Set of columns represent a compound or composite key –Identified by icon Foreign Key –Refers to the primary key columns in another table –Comprised of a column or set of columns

11. March 6, 2009 Joins Represent the Primary Key – Foreign Key relationships between tables in the Physical layer –Complex joins are used to express relationships that do not involve a Primary Key – Foreign Key relationship Used to formulate the join when building the SQL Joins Double-click to view Properties

12. March 6, 2009 Physical Layer Objects Are organized in the Administration Tool in a hierarchy: Maintains different schema definitions Represents the metadata

13. March 6, 2009 ABC Example Data sources for ABC reside in a normalized relational database containing tables with –Invoice data –Customer data –Product data –Period data Database or Data Source Import metadata using Analytics Administration Tool Source data Supplier Sales Supplier Sales

14. March 6, 2009 Implementation Steps  Define System Data Source Name (DSN) for data sources  Test connectivity to data sources  Import data source schemas  Edit connection pool properties  Define physical keys and join conditions if they were not imported

15. March 6, 2009 Define System DSN for Data Sources Use the ODBC Data Source Administrator to define a System DSN for each data source Provides the Analytics Server with information to connect to a the Supplier sales data source

16. March 6, 2009 Test Connectivity to Data Sources Use the OBI ODBC Client Tool to test the connection to physical data sources –Start > Programs > OBI > OBI ODBC Client Select File > Open Database to select the desired DSN Select Utility > Enter SQL Query to execute a query to verify your connection to the data source

17. March 6, 2009 Import Data Source Schemas Use the OBI Administration Tool to import the data source schema Select the Suppliers Sales database ODBC source to import metadata into the Physical layer

18. March 6, 2009 3/5 Import Data Source Schemas Continued Select the tables and columns needed to support the business model –Limit to tables and columns needed to support the users' analytic requirements Import the tables and columns identified in ABC’s business model

19. March 6, 2009 3/5 Import Data Source Schemas Continued Create the primary key – foreign key joins –Include the tables used to define the joins Select the type of metadata you want to import –Keys and foreign keys are imported automatically only if they are defined in the source data If primary key-foreign key rules have been defined in the source data, they will automatically be created during the import; otherwise you will need to define the keys manually Used to select table to display and import

20. March 6, 2009 4/5 Edit Connection Pool Properties Open the Connection Pool properties dialog box to ensure the Data Source Name field indicates the correct System DSN Specify a distinct name for the Connection Pool This is the system DSN that connects to the Suppliers sales data source Allow database connection to remain open until timeout after all requests complete Allows query cancellation to be sent to the database while the query is executing

21. March 6, 2009 4/5 Edit Connection Pool Properties Continued Specify the number of concurrent connections Enter the number of connections allowed for this connection pool

22. March 6, 2009 5/5 Define Physical Keys and Join Conditions The Administration Tool allows you to define physical keys and joins that were not imported automatically, in several different ways: –Define Primary Keys Using the Physical Table > Keys tab –Define Joins and Foreign keys Using the Physical Table Diagram Using the Joins Manager

23. March 6, 2009 Define Primary Keys Open the Table properties dialog box to define key column(s)‏ –Right-click a table and select Properties Select the Keys tab and click the New button Check the appropriate Column check-box

24. March 6, 2009 Define Joins Using Physical Table Diagram Use the Physical Table Diagram editor to: –View the table schema and joins –Define physical foreign keys and complex joins Complex joins are joins over non foreign key and primary key columns Double-click to open the Joins properties box

25. March 6, 2009 Define Foreign Keys From the Physical Table Diagram editor click the New Foreign Key button to join the tables The table you select first to create the join maintains the primary key, the table you select second maintains the foreign key to the first table The Joins properties box

26. March 6, 2009 Define Foreign Keys Continued From the Joins Property box click the column(s) that the foreign key joins Select columns in both the left and right tables By default the left side is the one side and the right side is the many

27. March 6, 2009 Define Joins Using Join Manager Use the Join Manager editor to: –View join relationships –Create physical foreign keys and complex joins

28. March 6, 2009 Many-to-Many Relationships Sometimes required between dimension tables and fact tables Require bridge tables that reside between the fact and dimension table in the data warehouse –Bridge table stores multiple records corresponding to that dimension –Example: Bridge table

29. March 6, 2009 Lab In the lab you will: –Build the Physical layer