Installation Guides > Installing Data Model > Supported upgrade paths > UNICOM Intelligence JDBC Driver guide > 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 Documentation 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
...
...
...
...
...
{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).
See also
UNICOM Intelligence JDBC Driver specification