string key, Value value)
Set user data
SQLHeavy user defined functions can store data in a hash table.
For scalar functions, this is uses the Function Auxillary Data (see http://sqlite.org/c3ref/get_auxdata.html) feature of SQLite, meaning that, "If the same value is passed to multiple invocations of the same SQL function during query execution, under some circumstances the associated metadata may be preserved."
For aggregate functions, it uses the Aggregate Function Context (see http://sqlite.org/c3ref/aggregate_context.html) feature of SQLite, allowing user data to be shared accross an entire aggregate operation.
| key | key of user data |
| value | value of user data |