tailieunhanh - HandBooks Professional Java-C-Scrip-SQL part 152

Tham khảo tài liệu 'handbooks professional java-c-scrip-sql part 152', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Quantum 443333333333222222222211111111110000000000 Offset 109876543210987654321098765432109876543210 - After we do the move the result looks like Figure itemref5. The data is in the right place now but the pointers are wrong. Specifically the m_Offset fields of the items that have higher item numbers than the one we have deleted are off by the length of the deleted field. That s why we have to call AdjustOffset to reduce the m_Offset field of every item after the deleted one by ItemLength which is the length of the deleted item. Then we set the data type of the deleted item in the item index to UNUSED ITEM. Sample IRA etc. during deletion Figure itemref5 - Quantum Item Index Number Number - Item I 0 I 3 2 Reference 1 I 3 4 _ - Array I 2 I 3 5 - - IRA I 3 I 3 3 I I I I 4 I 3 1 ------ I I I I I - I I I I I Item Offset Type Index ------------------ Item 1 5 - VARSTRING 4 -- Index 2 17 VARSTRING 0 -- for 3 -19 VARSTRING 3 Quantum 4 -34 VARSTRING 1 ----- 3 5 -41 VARSTRING 2 ------- 6 41 UNUSED 0 --- ------------- - ---------------- --------- ----------- - ----- -- -- ---------- - -------- Quantum Baldwin123 Main StreetSteve Heller11510 Data -------------------------------- - Quantum 443333333333222222222211111111110000000000 Offset 109876543210987654321098765432109876543210 - After correcting the index our quantum looks like Figure itemref6. We can now access the data in the quantum correctly as long as we use the official route through the IRA and the item Sample IRA etc. after deletion Figure itemref6 - Quantum Item Index Number Number - Item 0 3 2 Reference 1 3 4 - - Array 2 3 5 - - IRA 3 3 3 4 3 1 ---- - Item Offset Type Index ---------------- Item 1 5 - VARSTRING 4 -- Index 2 17 VARSTRING 0 -- for 3 17 UNUSED 0 Quantum 4 --32 VARSTRING 1 - 3 5 --39 VARSTRING 2 --- 6 39 UNUSED 0 -- ------------ - --------------- --------- -- - - ---- -- --------- ------- -- Quantum Baldwin123 Main StreetSteve Heller11510 Data ------------------------------------- - - .