Sequential File Organization (Cont.) Deletion-use pointer chains Insertion-locate the position where the record is to be inserted if there is free space insert there if no free space,insert the record in an overflow block In either case,pointer chain must be updated Need to reorganize the file 10101 Srinivasan Comp.Sci. 65000 from time to time to restore 12121 Wu Finance 90000 sequential order 15151 Mozart Music 40000 22222 Einstein Physics 95000 32343 El Said History 60000 33456 Gold Physics 87000 45565 Katz Comp.Sci. 75000 58583 Califieri History 62000 76543 Singh Finance 80000 76766 Crick Biology 72000 83821 Brandt Comp.Sci. 92000 98345 Kim Elec.Eng. 80000 32222 Verdi Music 48000 Database System Concepts-7th Edition 13.13 @Silberschatz,Korth and SudarshanDatabase System Concepts - 7 13.13 ©Silberschatz, Korth and Sudarshan th Edition Sequential File Organization (Cont.) ▪ Deletion – use pointer chains ▪ Insertion –locate the position where the record is to be inserted • if there is free space insert there • if no free space, insert the record in an overflow block • In either case, pointer chain must be updated ▪ Need to reorganize the file from time to time to restore sequential order