Return level field

JDBC Driver > UNICOM Intelligence JDBC Driver specification > Return level field

Return level field

In HDATA, array fields and grids field are considered level (hierarchical table).

If the query statement is SELECT * FROM HDATA, the current level is HDATA. If the query statement is SELECT * FROM HDATA.person, the current level is HDATA.person.

In the UNICOM Intelligence OLE DB Provider, when querying fields are the same as the current level (or upper, then current level), the field’s result should be considered as a normal field; otherwise querying fields are returned as a sub-table (level object).

Example: Query content level fields and parent level fields

Using data from the UNICOM Intelligence Developer Library household.mdd example:

SELECT
^.housetype
, ^.address
, levelid
, age
, person
FROM HDATA.person

The result data is:

^.housetype	^.address	levelid	age	person
{59}	15B Park Avenue, Harrogate, HG1 4TY	1	25	1
{61}	46 Freedom Lane, Brighton, BN2 3YT	1	45	2
{61}	46 Freedom Lane, Brighton, BN2 3YT	2	43	3
{61}	46 Freedom Lane, Brighton, BN2 3YT	3	15	4
{61}	46 Freedom Lane, Brighton, BN2 3YT	4	12	5
{60}	The Meadows, Clifton Heights, BS34 3EG	1	72	6
{60}	The Meadows, Clifton Heights, BS34 3EG	2	81	7
{62}	23 Steep Hill, Norfold, CB64 5TY	1	32	8
{62}	23 Steep Hill, Norfold, CB64 5TY	2	9	9
{62}	23 Steep Hill, Norfold, CB64 5TY	3	2	10
{61}		1	29	11
{61}		2	31	12
...	...	...	...	...

housetype	Address	levelid	age	person
{59}	15B Park Avenue, Harrogate, HG1 4TY	1	25	1
{61}	46 Freedom Lane, Brighton, BN2 3YT	1	45	2
		2	43	3
		3	15	4
		4	12	5
{60}	The Meadows, Clifton Heights, BS34 3EG	1	72	6
		2	81	7
{62}	23 Steep Hill, Norfold, CB64 5TY	1	32	8
		2	9	9
		3	2	10
{61}		1	29	11
		2	31	12
...	...	...	...	...

Return level object

Since the JDBC Driver only supports basic JDBC types, when the driver receives a level object from the UNICOM Intelligence OLE DB Provider, the driver transports the level object as a binary array. At the Java client site, users are able to identify column values as a level of a sub-table by using the data type. If you want to place data inside a sub-table, you must query data directly from the table (for example, SELECT * FROM HDATA.person).