CHECKSUM() of binary data

Hello,

I need to generate HASH of text values for my app. I can generate hash values for normal fields using CHEKCSUM and BINARY_CHECKSUM function but it does not support checksum of text, ntext, image, and cursor, as well as sql_variant.

How can I generate checksums of such datatype.

KaramCan anybody help me?|||CHECKSUM() by parts.
split ntext to blocks of nvarchar(4000) and use check sum.
Originally posted by karam_chand03
Hello,

I need to generate HASH of text values for my app. I can generate hash values for normal fields using CHEKCSUM and BINARY_CHECKSUM function but it does not support checksum of text, ntext, image, and cursor, as well as sql_variant.

How can I generate checksums of such datatype.

Karam|||Thanks for the answer.

Can I use it for datatypes like image, sql_variant?

A simple code on how to break it up and get a hash value will be helpful.|||Hello,

I am still unable to figure out but how can I generate checksum of the whole column in one SQL query? Is it possible?

Karam|||you can generate checksum() to whole column
like
select checksum(*) from tablename
provided none of the columns are of text ntext image data types
Originally posted by karam_chand03
Hello,

I am still unable to figure out but how can I generate checksum of the whole column in one SQL query? Is it possible?

Karam|||Hello,

Thats the problem. I do have those unsupported columns and I need to generate hash value from it. In MySQL (where I come from) has a md5() function to generate hash value dfor every type of data it supports.

What I can think of is that I can convert every such data to varbinary and then employ checksum on it. But that is failing as if I convert some char values to varbinary and then running checksum on it, it is returning the same data.

Is it feasible?

Karam|||I don't think so.
convert text to varchar and ntext to nvarchar....
and check.
Originally posted by karam_chand03
What I can think of is that I can convert every such data to varbinary and then employ checksum on it. But that is failing as if I convert some char values to varbinary and then running checksum on it, it is returning the same data.

Is it feasible?

Karam

CheckSum function

Why when I use different uniqueidentifier id will generate the same checksum
value? 911433607
SELECT checksum(CAST(('{A933B626-9F52-4D62-8B59-A7B1E1F243D0}') AS
uniqueidentifier))
SELECT checksum(CAST(('{844A9A36-3B5D-4359-8A62-A61A8836714F}') AS
uniqueidentifier))CHECKSUM won't produce a unique value for every conceivable input. How
could it, given that there are only a few billion possible checksums?
David Portas
SQL Server MVP
--|||To add to David's response:
http://www.cut-the-knot.org/do_you_know/pigeon.shtml
Adam Machanic
SQL Server MVP
http://www.datamanipulation.net
--
"Simon Lim" <Simon Lim@.discussions.microsoft.com> wrote in message
news:AAB87EED-C006-4F09-B302-6512F4A47E79@.microsoft.com...
> Why when I use different uniqueidentifier id will generate the same
checksum
> value? 911433607
> SELECT checksum(CAST(('{A933B626-9F52-4D62-8B59-A7B1E1F243D0}') AS
> uniqueidentifier))
>
> SELECT checksum(CAST(('{844A9A36-3B5D-4359-8A62-A61A8836714F}') AS
> uniqueidentifier))|||True also. thanks.
"Adam Machanic" wrote:

> To add to David's response:
> http://www.cut-the-knot.org/do_you_know/pigeon.shtml
>
> --
> Adam Machanic
> SQL Server MVP
> http://www.datamanipulation.net
> --
>
> "Simon Lim" <Simon Lim@.discussions.microsoft.com> wrote in message
> news:AAB87EED-C006-4F09-B302-6512F4A47E79@.microsoft.com...
> checksum
>
>