Questions about serial numbers

 <! -- After deletion, subtract 1 from the subsequent sequence number --> <statement id = "updatecollaboratornum" parameterclass = "Java. util. Map"> <! [CDATA [update tbzcollaborator set num = num-1 where branch_id = # branchid: varchar # And num> # num #]> </Statement> <! -- Change the new sequence number --> <statement id = "updatecollaboratornumfornewnum" parameterclass = "Java. util. Map"> <! [CDATA [update tbzcollaborator set num = # newnum # Where collaborator_id = # collaboratorid: varchar #]> </Statement> <! -- After the new sequence number is modified, the number of other sequence numbers is changed from small to large --> <statement id = "updateothercollaboratornumfornewnuma" parameterclass = "Java. util. Map"> <! [CDATA [update tbzcollaborator set num = num-1 where branch_id = # branchid: varchar # And num <= # newnum # And num> # num #]> </Statement> <! -- After the new sequence number is modified, the number of other sequence numbers is changed from large to small --> <statement id = "updateothercollaboratornumfornewnumd" parameterclass = "Java. util. Map"> <! [CDATA [update tbzcollaborator set num = num + 1 where branch_id = # branchid: varchar # And num <# num # And num >=# newnum #]> </Statement>