jakobbraun commented 4 years ago

Situation

Currently the precision of INTERVAL data types is hard-coded in the Exasol SQL dialect. The necessary information is not available via JDBC.

Acceptance Criteria

Ask the JDBC driver developers if it is possible to provide that precision via JDBC.
If yes: ticket for JDBC driver is created
If no: obtain precision from system tables

jakobbraun commented 4 years ago

jakobbraun commented 4 years ago

Result of discussion with JDBC driver developers:

JDBC column description has a limited number of standartized fileds.
Fraction precision(fp) is already mapped to DECIMAL_DIGITS
Precision(p) can not be mapped to COLUMN_SIZE since "For character data, this is the length in characters." and the Interval is a character column.
There is a hidden table"$ODBCJDBC".ALL_COLUMNS hat contains the COLUMN_TYPE column, which also includes the type definition as string like INTERVAL DAY(2) TO SECOND(7). We could parse this directly.
It would also be possible to create a different metadata info function then getColumns() in the JDBC driver to access this information. Compared to the previously described solution this would only bring a small performance gain (since it does use a faster internal API) and lots of effort for implementation.

jakobbraun commented 4 years ago

Alternatively we could propably also use SYS.EXA_ALL_COLUMNS, which also includes COLUMN_TYPE