Data mining — Activating a taxonomy

To activate a taxonomy, you must link the taxonomy to the mining field to be used as the item field. You can do this by using the method DM_setFldTax.

With the method DM_getFldTax, you can identify the taxonomy that is active for a mining field. You can link only categorical fields to a taxonomy.

If you remove a taxonomy by using the method DM_remTax, you also remove the link from the taxonomy to the mining field.

Example

You might have the following tables:

MYSCHEMA.MY_TAXTABLE

The table MYSCHEMA.MY_TAXTABLE contains items in the column ITEMCOL and categories in the column CATMAPCOL_1.

Table 1. MYSCHEMA.MY_TAXTABLE
`ITEMCOL`	`CATMAPCOL_1`
138	160
139	160
140	161
141	161

MYSCHEMA.MY_ITEM_NMPTABLE

The table MYSCHEMA.MY_ITEM_NMPTABLE contains name mappings for the items in the columns ITEMCOL and ITEMNAME_COL.

Table 2. MYSCHEMA.MY_ITEM_NMPTABLE
`ITEMCOL`	`ITEMNAME_COL`
138	Beer
139	Wine
140	Mineral water
141	Coke

MYSCHEMA.MY_CAT_NMPTABLE

The table MYSCHEMA.MY_CAT_NMPTABLE contains name mappings for the categories in the columns CAT_COL and CATNAME_COL.

Table 3. Contents of the table MYSCHEMA.MY_CAT_NMPTABLE
`CATCOL`	`CATNAME_COL`
160	Alcoholic drink
161	Non-alcoholic drink

You might want to define a taxonomy and assign it to the field COL1. In the physical data table, the column that is mapped to COL1 later when a task is defined must contain the values 138, 139, 140, and 141 in order to make the taxonomy effective. The SQL statement looks like this:

IDMMX.DM_LogicalDataSpec()..DM_addDataSpecFld('COL1')
      ..DM_addTax('MyTax', 'MYSCHEMA.MY_TAXTABLE', 'ITEMCOL', 
                           'CATMAPCOL_1', cast(NULL as VARCHAR), 0)
      ..DM_setFldTax('COL1','MyTax')

In the taxonomy table CatMapNmp, you might want to define a taxonomy and assign it to the field COL1. In addition, you might want to define the name mapping ItemNmp for the field COL1 and for the category field CATMAPCOL_1.

IDMMX.DM_LogicalDataSpec()..DM_addDataSpecFld('COL1')
      ..DM_addNmp('ItemNmp', 'MYSCHEMA.MYNMPTABLE', 
                             'ITEMCOL', 'MAPPEDITEMCOL')
      ..DM_addNmp('CatMapNmp', 'MYSCHEMA.MYNMPTABLE',
                               'VALUECOL','MAPPEDVALUECOL')
      ..DM_setFldNmp('COL1', 'ItemNmp')
      ..DM_addTax('MyTax', 'MYSCHEMA.MYTAXTABLE', 'ITEMCOL', 
                           'CATMAPCOL_1', 'CatMapNmp', 0)
      ..DM_setFldTax('COL1','MyTax')