username upper case lower case how to fix

  • there is a field userid, firstname and last name which is allowing such userids Allowing upper case and Lowercase  , How to fix it so it does not allow upper case/lower case and considers it duplicate?


    userid firstname lastname

    aina aina aina

    Aina Aina Aelson

    Thanks in Advance



  • That's somewhat confusing.  Do you want to not allow mixed case at all?  Or do you just want to prevent a duplicate from being inserted, basically ignoring case in determining dup?

    SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.

  • prevent duplicates, ignoring case would be better

  • You've got some choices, some more annoying than others:

    (1) Use an INSERT trigger to check for dups and cancel if a dup would be created.

    (2) Create additional columns that are case sensitive and build a UNIQUE index on those columns.

    (3) Change the original columns to case sensitive and then build a UNIQUE index on the columns.

    SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.

  • What collation are you using for these columns ?

    If you are actually using case sensitive collations:

    How about using lower(userid) , lower(name) and lower(firstname) with the insert statement

    or have a persisted computed column performing the concat using these functions and put a unique index on that one.

    -- add this computed column
    , [userid_name_firstname] AS concat(lower(userid), lower(name),lower(firstname)) PERSISTED


    create unique index x_userid_name_firstname on yourschema.yourtable( userid_name_firstname )


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