6-22 Metadata Repository Builders Guide for Oracle Business Intelligence Enterprise Edition
5.
Optional To set write-back properties, click the Connection Pools tab.
6.
In the connection pool list, double-click the connection pool.
7.
In the Connection Pool dialog, click the Write Back tab.
8.
Complete the fields using Table 6–7
as a guide. See also About Setting the Buffer
Size and Transaction Boundary for additional information.
9. Click OK, then click OK again to save the persist connection pool.
To remove a persist connection pool: 1.
In the Physical layer of the Administration Tool, double-click the database object that contains the persist connection pool you want to remove.
2.
In the Database dialog, click the General tab.
3. In the Persist connection pool area, click Clear.
The database name is replaced by not assigned in the Persist connection pool field.
4. Click OK.
About Setting the Buffer Size and Transaction Boundary
If each row size in a result set is 1 KB and the buffer size is 20 KB, then the maximum array size is 20 KB. If there are 120 rows, there are 6 batches with each batch size
limited to 20 rows.
If you set Transaction boundary to 3, the server commits twice. The first time, the server commits after row 60 3 20. The second time, the server commits after row
120. If there is a failure when the server commits, the server only rolls back the current transaction. For example, if there are two commits and the first commit succeeds but
the second commit fails, the server only rolls back the second commit.
For optimum performance, consider setting the buffer size to 128 and the transaction boundary to 1000.
7
Working with Physical Tables, Cubes, and Joins 7-1
7
Working with Physical Tables, Cubes, and Joins
The Physical layer of the Oracle BI repository contains objects that represent physical data constructs from back-end data sources. The Physical layer defines the objects and
relationships available to the Oracle BI Server for writing physical queries. This layer encapsulates data source dependencies to enable portability and federation.
Each data source of the repository model typically has its own discrete physical model in the Physical layer. The top-level object in the Physical layer is a database, and the
type of database determines which features and rules apply to that physical model. For example, a relational database such as Oracle 11g has relational objects such as
physical tables and joins. In contrast, a multidimensional source such as Essbase 9 has cube tables and physical hierarchies. Therefore, some sections of this chapter
apply to only certain database types.
Physical tables, cubes, joins, and other objects in the Physical layer are typically created automatically when you import metadata from your data sources. After these
objects have been imported, you can perform tasks like creating additional join paths that are not in the data source, create alias tables for physical tables that need to serve
in different roles, and adjust properties of physical hierarchies from multidimensional data sources.
This chapter contains the following topics:
■
Working with the Physical Diagram
■
Creating Physical Layer Folders
■
Working with Physical Tables
■
Working with Multidimensional Sources in the Physical Layer
■
Working with Essbase Data Sources
■
Working with Hyperion Financial Management Data Sources
■
Working with Oracle OLAP Data Sources
■
Working with Physical Foreign Keys and Joins
■
Deploying Opaque Views
■
Using Hints
■
Displaying and Updating Row Counts for Physical Tables and Columns
7-2 Metadata Repository Builders Guide for Oracle Business Intelligence Enterprise Edition
Working with the Physical Diagram
In addition to working with Physical layer objects in the right pane of the Administration Tool, you can open the Physical Diagram view to see a graphical
model of tables and joins.
To access the Physical Diagram, right-click an object in the Physical layer tree view such as a physical database or table and select Physical Diagram. Then, select one of
the following options:
■
Selected Objects Only. Displays only the selected objects. Joins appear only if
they exist between the objects that you select.
■
Objects and Direct Joins. Displays the selected objects and any tables that join to
the objects that you select.
■
Objects and All Joins. Displays the selected objects, as well as each object that is
related directly or indirectly to the selected object through some join path. If all the objects in a schema are related, then using this option diagrams every table, even if
you only select one table.
Note that the Physical Diagram displays only physical tables and joins. It does not display other Physical layer objects, such as connection pools, physical hierarchies, or
levels.
Figure 7–1 shows the Physical Diagram.
Note: The Physical Diagram is typically used with relational and
XML sources rather than multidimensional sources. Although the Physical Diagram view for a multidimensional source does display a
denormalized table representation of a cube table, the primary means of working with a multidimensional physical model is by working in
the physical tree using dimensions, hierarchies and columns.
Working with Physical Tables, Cubes, and Joins 7-3
Figure 7–1 Physical Diagram
You can also open the Physical Diagram by selecting one or more objects in the tree view and then clicking the Physical Diagram button on the toolbar:
Only the objects you selected appear. Joins appear only if they exist between the selected objects. Joins are represented by a line with an arrow at the one end of the
join.
To help you better understand the logical-to-physical mappings in your model, you can view the physical objects that are associated with a particular logical object by
selecting one or more business models, logical tables, or logical table sources in the Business Model and Mapping layer tree view and then clicking the Physical Diagram
button on the toolbar. Only physical objects that are related to the objects you selected appear. You can view the same information by right-clicking a logical object and
selecting Objects and Direct Joins within Business Model from the Physical Diagram submenu. You can also choose one of the other Physical Diagram display
options.
7-4 Metadata Repository Builders Guide for Oracle Business Intelligence Enterprise Edition
To add additional tables to the Physical Diagram, leave the Physical Diagram window open and then right-click the table or tables you want to add. Then, select Physical
Diagram and choose one of the display options.
Additional options are available in the right-click menu for the graphical tables and joins displayed in the Physical Diagram. For example, you can delete objects or view
their properties, or you can add additional related objects using the right-click options Add Direct Joins
, Add Tables Joined to Whole Selection, and Add All Joins. You can also select Find in Tree View to locate a particular object in the Physical layer tree
view in the right pane, or check out objects in online mode.
You can also right-click an object in the Physical Diagram view and select Hide to hide particular objects in the diagram. Note that this effect is temporary and does not
persist.
See also the following sections:
■
Using the Physical and Business Model Diagrams for information about
zooming, panning, and controlling the layout of the tables
■
Defining Physical Joins with the Physical Diagram for information about
defining physical joins
Creating Physical Layer Folders
This section contains the following topics:
■
Creating Physical Layer Catalogs and Schemas
■
Using a Variable to Specify the Name of a Catalog or Schema
■
Setting Up Display Folders in the Physical Layer
Creating Physical Layer Catalogs and Schemas
Catalogs are optional ways to group different schemas. A catalog contains all the schemas metadata for a physical database object. A schema contains only the
metadata information for a particular user or application. Model the Physical layer after the way your data source is structured.
Note the following:
■
You must create a physical database object before you can create a physical catalog object or a physical schema object.
■
After you implement a certain type of grouping, you cannot change it later. For example, if you decide to implement database schema table, you cannot add a
catalog afterward.
Creating Catalogs
In the Physical layer of a large repository, administrators can create physical catalogs that contain one or more physical schemas.
To create a catalog: 1.
In the Physical layer of the Administration Tool, right-click a physical database and select New Object, then select Physical Catalog.
2.
In the Physical Catalog dialog, type a name for the catalog.
3. Type a description for the catalog, and then click OK.
