Database Access
In order to access the root object space, the database header has to be read. The database header it the database entry with LOID 1:
DBHeader
|
Pos |
Size |
|
|
0 |
4 |
DB header identifier (DBHn, where n is the header version) |
|
4 |
2 |
Last complex data type number |
|
6 |
8 |
Database global identifier (GUID) |
|
14 |
137 |
Recover file information |
|
151 |
1 |
Replication database indicator |
|
152 |
4 |
LOID for root object space (uint32) |
|
156 |
4 |
Next work space number |
|
160 |
8 |
LOID for shadow database |
|
168 |
26 |
LOID for version list (versioning schema) |
|
194 |
1 |
Indicates save transactions |
|
195 |
1 |
Reserved for future use |
|
196 |
4 |
Maximum number of replication server transactions |
|
200 |
4 |
Number of last transaction written |
|
204 |
1 |
Indicates an encoded database |
|
205 |
50 |
Reserved for future use |
The root object space LOID refers to the object space instance:
SDB_ObjectExt
|
Pos |
Size |
|
|
0 |
8 |
Reserved for future use |
|
8 |
8 |
LOID to extent list |
|
16 |
8 |
Reserved for future use |
|
24 |
4 |
Internal object space identification (int32) |
|
28 |
4 |
Current object space version |
The LOID to the extent index, which is an ordered list with extent names and LOID to the collection:
ExtentListEntry
|
Pos |
Size |
|
|
0 |
8 |
Extent LOID |
|
48 |
40 |
Extent name |
|
52 |
4 |
Internal namespace number |
The extent LOID is a reference to a collection, i.e. a collection LOID.