Most of DBMS (MSSQL, Db2, Oracle, MySQL, ...) supports index based on SQL expressions, instead of using full column content.
This is an important feature, as the index is better used per application needs.
DF Driver does not support such indexes yet.. I mean, you can create such indexes, and create filters using SqlFilters, but there are still space for enhancements.
Filling grids for example, by using expression ordering matching the index definition.
Basically, we need to be able to specify SQL expression on index keys segments, instead of just providing a column name.
This is a Db2 example, of a index defined in a Json element:
Code:
CREATE UNIQUE INDEX "DB2ADMIN"."IX_CUST_STATE" ON "DB2ADMIN"."CUSTOMER_JSON"
( JSON_VALUE(JSON_DATA, '$.contact.state' RETURNING CHAR(2)) ASC,
"CUSTOMER_ID" ASC)
But on DF layer, the first index segment is unknown..
So, this index can`t be used by DF to perform finds or ordering.
The expression could be any SQL expression returning an scalar value.
Regards