DRILL-2465: Fix multiple DatabaseMetaData.getColumns() bugs.
- Added test DatabaseMetaDataGetColumnsTest.
- (Renamed Drill2128GetColumnsBugsTest to
Drill2128GetColumnsDataTypeNotTypeCodeIntBugsTest.)
- Fixed/implemented various columns:
- Added COLUMN_SIZE (big CASE expression handling lots of cases).
- Fixed DECIMAL_DIGITS.
- Fixed NUM_PREC_RADIX.
- ~Fixed REMARKS ('' -> NULL).
- ~Fixed COLUMN_DEF ('' -> NULL).
- Fixed CHARACTER_OCTET_LENGTH.
- Fixed ORDINAL_POSITION.
- Fixed SCOPE_CATALOG, SCOPE_SCHEMA, SCOPE_TABLE,
- Fixed SOURCE_DATA_TYPE.
- Note: INTERVAL types have only *interim* implementations.
(INFORMATION_SCHEMA.COLUMNS fixes are needed for completion.)
- Added canonical data type name strings in DATA_TYPE -> TYPE_NAME CASE
expression (for robustness for expected upcoming INFORMATION_SCHEMA.COLUMNS
standard-compliance bug fixing).
