To create a filter expression
You can use a filter expression (WHERE clause expression) to update your partition with only a subset of the data in the fact table.
Caution If in the preceding step of the wizard, you selected the default fact table (that is, the same table already used as the partition’s fact table), you must use a filter expression to ensure that only data not already in the partition is added. Otherwise, the cube containing the partition will contain duplicate and therefore inaccurate data.
For example, the partition contains data for years 1995 through 1997. You are adding data for 1998 from the same table that supplies the 1995 through 1997 data. The name of the column that contains years is the_year. You must use the following filter expression:
"the_year"=1998
Another example (alphanumeric data):
"the_month"='January'
Whenever necessary to avoid ambiguity, use a qualified expression. For example, if a column name appears in multiple tables, include the table name in the expression:
"time"."the_month"='January'
The SELECT statement used to retrieve records for the incremental update is generated automatically by the wizard. The filter expression is connected with an AND to the automatically generated part of the WHERE clause. Therefore, if you specify multiple filter expressions, enclose them all in a pair of parentheses. Example:
("the_year"=1998 OR "the_year"=1999)
Filters consist of one or more expressions using columns in the fact table. A filter can also contain columns in dimension tables if they are included in a nested SELECT statement and the underlying database supports nested SELECT statements. For more information, see Filters.
The filter expression acts as a pass-through statement, and its syntax is not checked until you finish the wizard. If the syntax is incorrect, the incremental update fails.
To create a filter expression