Change Implementation of Select, Update, and Insert in SQL Server -

to give question first: want know if possible create stored procedure or in sql server intercepts , translates select, insert, , update commands. explanation:

i writing web application replace old desktop app. business app database interface reports , searches , ol' crud. new , old apps need live in harmony since customers may using old , new access same db.

my problem original database format stores data in single blob of text (1 nvarchar(max) field). want add functionality search on fields stored in blob, cumbersome , slow. update database format without changing desktop app @ all, hence question above.

it occurs me on client writing wrapper class data access object , bulk replace in client code reference wrapper, want know options on server well.

in case wants know, old app in vb6 , new in c#.

edit

alright, looks if on server side looking @ adding stored procedures , updating client vb6 code reference stored procs. bulk replace of select sp_oldselect ... return data in different format. i'm guessing client-side wrapper best solution time-being. old apps die hard.

you can create bunch of views old client , let query views. slow hell in cases, can 'replace' select query. updates , insert.. well.. instead of triggers on views could cases, require lots of processing.

however suggestion provide same functionality in web app , deprecate desktop app. when desktop app's share low enough, stop supporting it. point, (mostly) free add new functions, upgrade database schema, etc.