38.1 CLUSTER_DETAILS
Syntax
cluster_details::=
Analytic Syntax
cluster_details_analytic::=
mining_attribute_clause::=
mining_analytic_clause::=
See Also:
"Analytic Functions" for information on the syntax, semantics, and restrictions of mining_analytic_clause
Purpose
CLUSTER_DETAILS
returns cluster details for each row in the selection. The return value is an XML string that describes the attributes of the highest probability cluster or the specified cluster_id
.
topN
If you specify a value for topN
, the function returns the N
attributes that most influence the cluster assignment (the score). If you do not specify topN
, the function returns the 5 most influential attributes.
DESC, ASC, or ABS
The returned attributes are ordered by weight. The weight of an attribute expresses its positive or negative impact on cluster assignment. A positive weight indicates an increased likelihood of assignment. A negative weight indicates a decreased likelihood of assignment.
By default, CLUSTER_DETAILS
returns the attributes with the highest positive weights (DESC
). If you specify ASC
, the attributes with the highest negative weights are returned. If you specify ABS
, the attributes with the greatest weights, whether negative or positive, are returned. The results are ordered by absolute value from highest to lowest. Attributes with a zero weight are not included in the output.
Syntax Choice
CLUSTER_DETAILS
can score the data in one of two ways: It can apply a mining model object to the data, or it can dynamically mine the data by executing an analytic clause that builds and applies one or more transient mining models. Choose Syntax or Analytic Syntax:
-
Syntax — Use the first syntax to score the data with a pre-defined model. Supply the name of a clustering model.
-
Analytic Syntax — Use the analytic syntax to score the data without a pre-defined model. Include
INTO
n
, wheren
is the number of clusters to compute, andmining_analytic_clause
, which specifies if the data should be partitioned for multiple model builds. Themining_analytic_clause
supports aquery_partition_clause
and anorder_by_clause
. (See "analytic_clause::=".)
The syntax of the CLUSTER_DETAILS
function can use an optional GROUPING
hint when scoring a partitioned model. See GROUPING Hint.
mining_attribute_clause
mining_attribute_clause
identifies the column attributes to use as predictors for scoring. When the function is invoked with the analytic syntax, these predictors are also used for building the transient models. The mining_attribute_clause
behaves as described for the PREDICTION
function. (See "mining_attribute_clause".)
See Also:
-
Oracle Data Mining User's Guide for information about scoring.
-
Oracle Data Mining Concepts for information about clustering.
Note:
The following examples are excerpted from the Data Mining sample programs. For more information about the sample programs, see Appendix A in Oracle Data Mining User's Guide.
Example
This example lists the attributes that have the greatest impact (more that 20% probability) on cluster assignment for customer ID 100955. The query invokes the CLUSTER_DETAILS
and CLUSTER_SET
functions, which apply the clustering model em_sh_clus_sample
.
SELECT S.cluster_id, probability prob, CLUSTER_DETAILS(em_sh_clus_sample, S.cluster_id, 5 USING T.*) det FROM (SELECT v.*, CLUSTER_SET(em_sh_clus_sample, NULL, 0.2 USING *) pset FROM mining_data_apply_v v WHERE cust_id = 100955) T, TABLE(T.pset) S ORDER BY 2 DESC; CLUSTER_ID PROB DET ---------- ----- --------------------------------------------------------------------------------- 14 .6761 <Details algorithm="Expectation Maximization" cluster="14"> <Attribute name="AGE" actualValue="51" weight=".676" rank="1"/> <Attribute name="HOME_THEATER_PACKAGE" actualValue="1" weight=".557" rank="2"/> <Attribute name="FLAT_PANEL_MONITOR" actualValue="0" weight=".412" rank="3"/> <Attribute name="Y_BOX_GAMES" actualValue="0" weight=".171" rank="4"/> <Attribute name="BOOKKEEPING_APPLICATION" actualValue="1" weight="-.003"rank="5"/> </Details> 3 .3227 <Details algorithm="Expectation Maximization" cluster="3"> <Attribute name="YRS_RESIDENCE" actualValue="3" weight=".323" rank="1"/> <Attribute name="BULK_PACK_DISKETTES" actualValue="1" weight=".265" rank="2"/> <Attribute name="EDUCATION" actualValue="HS-grad" weight=".172" rank="3"/> <Attribute name="AFFINITY_CARD" actualValue="0" weight=".125" rank="4"/> <Attribute name="OCCUPATION" actualValue="Crafts" weight=".055" rank="5"/> </Details>
Analytic Example
This example divides the customer database into four segments based on common characteristics. The clustering functions compute the clusters and return the score without a predefined clustering model.
SELECT * FROM ( SELECT cust_id, CLUSTER_ID(INTO 4 USING *) OVER () cls, CLUSTER_DETAILS(INTO 4 USING *) OVER () cls_details FROM mining_data_apply_v) WHERE cust_id <= 100003 ORDER BY 1; CUST_ID CLS CLS_DETAILS ------- --- ----------------------------------------------------------------------------------- 100001 5 <Details algorithm="K-Means Clustering" cluster="5"> <Attribute name="FLAT_PANEL_MONITOR" actualValue="0" weight=".349" rank="1"/> <Attribute name="BULK_PACK_DISKETTES" actualValue="0" weight=".33" rank="2"/> <Attribute name="CUST_INCOME_LEVEL" actualValue="G: 130\,000 - 149\,999" weight=".291" rank="3"/> <Attribute name="HOME_THEATER_PACKAGE" actualValue="1" weight=".268" rank="4"/> <Attribute name="Y_BOX_GAMES" actualValue="0" weight=".179" rank="5"/> </Details> 100002 6 <Details algorithm="K-Means Clustering" cluster="6"> <Attribute name="CUST_GENDER" actualValue="F" weight=".945" rank="1"/> <Attribute name="CUST_MARITAL_STATUS" actualValue="NeverM" weight=".856" rank="2"/> <Attribute name="HOUSEHOLD_SIZE" actualValue="2" weight=".468" rank="3"/> <Attribute name="AFFINITY_CARD" actualValue="0" weight=".012" rank="4"/> <Attribute name="CUST_INCOME_LEVEL" actualValue="L: 300\,000 and above" weight=".009" rank="5"/> </Details> 100003 7 <Details algorithm="K-Means Clustering" cluster="7"> <Attribute name="CUST_MARITAL_STATUS" actualValue="NeverM" weight=".862" rank="1"/> <Attribute name="HOUSEHOLD_SIZE" actualValue="2" weight=".423" rank="2"/> <Attribute name="HOME_THEATER_PACKAGE" actualValue="0" weight=".113" rank="3"/> <Attribute name="AFFINITY_CARD" actualValue="0" weight=".007" rank="4"/> <Attribute name="CUST_ID" actualValue="100003" weight=".006" rank="5"/> </Details>