Play the InfoMap Game
an information map bridges the gap between the:
- the physical data warehouse
- business user who views or builds reports from the data
- information architects sees physical data source that might be an array of interconnected tables and columns
- business users sees a simple list of business terms
an information map:
- enables business users access to the most current data that is needed for business reporting
- hides from business users the details of the physical data view
Information maps are :
user-friendly metadata definitions of physical data sources.
information map contains two basic elements:
A data item (a table column, an OLAP hierarchy, or an OLAP measure) –
- are used for building queries and can be an item that represents either physical data or a calculation.
- are usually customized in order to present the physical data in a form that is relevant and meaningful to a business user.
A filter is criteria that subset the data (i.e. where clause).
SAS Information Maps contain metadata to describe the following elements:
Metadata about the data sources: An information map can be based on SAS data sets, SAS OLAP cubes, or a third-party database such as Oracle, Teradata, DB2, or Microsoft Excel
Metadata about relationships : Multiple relational data tables can be combined or joined to enable optimized queries, regardless of the data source.
Metadata about the appearance and usage of data items : control the display of data items through labels and formats. It can also control the usage of the data items. For example, you can decide that a certain data item should not be used in a sort or to compute statistics.
Metadata about business rules : Standard calculations and filters can be predefined so that business users do not need to re-create them every time that they are needed.
Metadata Repository pane on left: display of the information maps
Presentation tab: physical data sources, data items, and filters
Physical data on left : shows physical data sources
Information Map: details panel displays the Information Map data items and filters
Relationship Tab: Tables and their relationships to others
You cannot use both a table and a cube in the same information map
By inserting a data source for your information map, you have made the data available to the information map.
Now, you must create data items in order to include them in the information map.
A business user sees data from the data source only if you create a data item to represent it.
- A data item can be a logical view of a field in the physical data.
- A data item can be calculated from an expression.
To create data items, you use the Presentation tab of the main SAS Information Map Studio window.
To create a data item that is a logical view of the physical data field, you select an item in the Physical Data pane, and you use the Insert button to create a corresponding data item in the Information Map pane.
Data items are listed in the Information Map pane with an icon indicating their classification. There are two classes of data items
category: distinct value that is used to group or summarize measure data items
measured: a value that is measured and can be used in expression
Each data item has metadata to describe its properties
You can view and edit a data item’s properties in the Data Item Properties window
you right-click the data item in the Information Map pane of the Presentation tab and select Properties
Filters : A filter can also be based on a physical data column or on an expression. The expression that you use in a filter can reference data items, physical data columns, or both.
category data item:
- query code uses a WHERE clause
- the clause is evaluated for individual records prior to any aggregations
measure data item:
- query code uses a HAVING clause
- the clause is evaluated on summarized information after aggregating the data
To open the New Filter window, you click the New Filter tool
In the Data item box, you specify the data item, physical column, or expression to which this filter applies.
In the Condition box, you specify the condition that is used to filter the data. For relational filters, the list of available conditions is based on the data item that is selected in the Data item box.
In the Value(s) box, you specify the unformatted values that the condition uses to filter the data items
You click Combinations to display or hide the elements that enable you to create compound expressions for the filter. Or/And expressions
he Edit button on the Definition tab enables you to open the Expression Editor window, where you can specify an expression for the new data item.
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