neodatis.odb 第一篇存储对象的偏移地址

最新推荐文章于 2022-12-13 22:41:37 发布

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#存储 #object #class #header #attributes #reference

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本文详细介绍了数据库文件中各类对象的存储结构与偏移地址，包括数据库头信息、类偏移块、对象偏移块等内容，为理解数据库内部机制提供了基础。

数据库文件存储对象的偏移地址

DB_HEADER_VERSION_POSITION is: 0
DB_HEADER_DBID_POSITION is: 1
DB_HEADER_NUMBER_OF_CLS_POSITION is: 33
DB_HEADER_FIRST_CLS_OID is: 37
DB_HEADER_LAST_CLOSE_STATUS_POSITION is: 45

DB_HEADER_DB_IS_USER_PROTECTED is: 46
DB_HEADER_DB_USERNAME is: 47
DB_HEADER_DB_PASSWORD is: 97
DB_HEADER_CURRENT_ID_BLOCK_POSITION is: 147
DB_HEADER_FIRST_ID_BLOCK_POSITION is: 155

CLASS_OFFSET_BLOCK_SIZE is: 0
CLASS_OFFSET_BLOCK_TYPE is: 4
CLASS_OFFSET_CATEGORY is: 5
CLASS_OFFSET_ID is: 6
CLASS_OFFSET_PREVIOUS_CLASS_POSITION is: 14
CLASS_OFFSET_NEXT_CLASS_POSITION is: 22
CLASS_OFFSET_CLASS_NB_OBJECTS is: 30
CLASS_OFFSET_CLASS_FIRST_OBJECT_POSITION is: 38
CLASS_OFFSET_CLASS_LAST_OBJECT_POSITION is: 46
CLASS_OFFSET_CLASS_NAME_SIZE is: 30

OBJECT_OFFSET_BLOCK_SIZE is: 0
OBJECT_OFFSET_BLOCK_TYPE is: 4
OBJECT_OFFSET_OBJECT_ID is: 5
OBJECT_OFFSET_CLASS_INFO_ID is: 13
OBJECT_OFFSET_PREVIOUS_OBJECT_OID is: 21
OBJECT_OFFSET_NEXT_OBJECT_OID is: 29
OBJECT_OID is: 37
OBJECT_CREATION_DATE is: 45
OBJECT_UPDATE_DATE is: 53
OBJECT_VERSION is: 61
OBJECT_REFERENCE_POINTER is: 65
OBJECT_IS_EXTERNALLY_SYNCHRONIZED is: 73
OBJECT_NB_ATTRIBUTES is: 74

BLOCK_ID_REPETITION_ID_TYPE is: 0
BLOCK_ID_REPETITION_ID is: 1
BLOCK_ID_REPETITION_ID_STATUS is: 9
BLOCK_ID_REPETITION_OBJECT_POSITION is: 10

NATIVE_OBJECT_OFFSET_BLOCK_SIZE is: 0
NATIVE_OBJECT_OFFSET_BLOCK_TYPE is: 4
NATIVE_OBJECT_OFFSET_ODB_TYPE_ID is: 5
NATIVE_OBJECT_OFFSET_OBJECT_IS_NULL is: 9
NATIVE_OBJECT_OFFSET_DATA_AREA is: 10