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First, open the context menu of the Search Rule Set node and select New Stopwords (table-based) or New
Term Mappings (table based).
In the properties of the new nodes, you can define the stopword table and term mapping table that is used.
On the Stopwords (table-based) or Term Mappings (table-based) node, select New Column to enable the
stopwords or term mappings on a column. In the properties panel, you can define the name of the column
where stopwords and term mappings shall be applied.
Below the Column nodes, create new List ID nodes (open the context menu and select New List ID). In each
list ID node, you can configure a stopword or term mapping list that is applied on the column.
The stopword and term mapping settings are valid for a given column in all rules.
Executing a Search With a Rule Set
HANA exports a new built-in function: SYS.EXECUTE_SEARCH_RULE_SET, with which you can execute a
previously defined search rule set.
The function has one parameter, which is an XML string to run the search. Within this XML, you have to specify:
● The ruleset that should be executed
● The way the result will be returned
● The limitation of the result
● The input values
The EXECUTE_SEARCH_RULE_SET method returns by default a ResultSet object. This object contains all the
columns from the referenced attribute view plus additional columns _SCORE and _RULE_ID. Alternatively, the
EXECUTE_SEARCH_RULE_SET can write the result into a results table that needs to be created by the user.
For code samples of SYS.EXECUTE_SEARCH_RULE_SET calls, see Search with a Rule Set - Code Samples [page
304].
Transaction Isolation Level
The EXECUTE_SEARCH_RULE_SET function creates one SELECT statement for each of the rules and runs the
statements independent of each other. The statements are executed in the transaction context of the calling
application and use the same isolation level as the application. The isolation level has an influence on the results of
the EXECUTE_SEARCH_RULE_SET function when there are other transactions running in parallel that change the
contents of the database tables.
When the isolation level 'READ COMMITTED' is used, each of the SELECT statements of the search rule set sees
all changes that have been committed at the time the execution of the SELECT statement begins. So, for example,
the second rule of a rule set may see a new record that was not committed when the first rule has been executed.
In this case, the new record may be returned by the 'wrong' rule and the user gets an incorrect result.
When the isolation levels 'REPEATABLE READ' or 'SERIALIZABLE' are used, all SELECT statements see the same
state of the database. So the results returned by EXECUTE_SEARCH_RULE_SET are always correct.
Search with a Rule Set - Code Samples
Executing a search and returning the result as a ResultSet:
CALL SYS.EXECUTE_SEARCH_RULE_SET('
-- specifies the SearchRuleSet
Herbert -- specifies the input value
for column FIRSTNAME
304
P U B L I C
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SAP HANA Developer Guide
Enabling Search