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RE: CASTing

Michael Spencer — Fri, 30 May 2008 10:55:47 GMT

[quote] think these two QODs really show how evil implicit type conversions are.Id rather spend this one second on explicit type conversion than on reviewing such code for possible data loss caused by implicit conversion. I had to look at this QOD for at least 5 seconds before I made my choice. Sum this up for all your code and then tell me: wouldn't it be great if the compiler told you when you had missed a type conversion?Sure, you have a test team, but why not catch an error in the first place?Isn't a database a realm where datatypes should be handled in the most strict way?Just some thoughts in the late evening :-) Best Regards,Chris Büttner [/quote]I totally agree after thinking about these two QOD (great ones, btw). Is there a way to enable explicit (strict) conversions when writing stored procedures in SQL 2005?

RE: CASTing

dan.deluna — Fri, 30 May 2008 05:42:17 GMT

Thanks for the clarification. :D

RE: CASTing

Christian Buettner-167247 — Thu, 29 May 2008 14:01:44 GMT

I think these two QODs really show how evil implicit type conversions are.Id rather spend this one second on explicit type conversion than on reviewing such code for possible data loss caused by implicit conversion. I had to look at this QOD for at least 5 seconds before I made my choice. Sum this up for all your code and then tell me: wouldn't it be great if the compiler told you when you had missed a type conversion?Sure, you have a test team, but why not catch an error in the first place?Isn't a database a realm where datatypes should be handled in the most strict way?Just some thoughts in the late evening :-)

RE: CASTing

Biggles-581128 — Thu, 29 May 2008 09:30:02 GMT

Great question.Didn't fall into the trap, but only because I remembered the question 2 days ago and thought there must be something else going on.Its got me thinking a lot more about types and implicit conversions. Thanks

RE: CASTing

John Mitchell-245523 — Thu, 29 May 2008 08:49:05 GMT

Yeah, so did I. I see what happened now.John

RE: CASTing

Jason Shadonix — Thu, 29 May 2008 08:47:42 GMT

Good question of the day...I totally fell for it!

RE: CASTing

steveb. — Thu, 29 May 2008 08:41:55 GMT

nvarchar has a max length of 4000 not 8000the 'N' in this statment converts it;[code]set @c = N'hello'[/code]

RE: CASTing

Jerry Hung — Thu, 29 May 2008 08:36:34 GMT

Does that mean this 2 lines below, converts @c to nvarchar(8000)?meaning ANY casting to nvarchar always give it maximum length of 8000?[quote]declare @c varchar(800)set @c = N'hello' [/quote]I think I got lost by reading this sentence ... maybe I shouldn't read it anymore[quote]The CAST to nvarchar(800) has a maximum 4000 character len.[/quote]

RE: CASTing

steveb. — Thu, 29 May 2008 08:25:13 GMT

The one two days ago was casting to a length greater than the nvarchar data type max of 4000, so the length was truncated to 4000. The one today was casting to a length less than 4000 so it stayed the same.

RE: CASTing

Jerry Hung — Thu, 29 May 2008 08:13:07 GMT

me a little bit confused too, what's the difference between this Question, and the one 2 days ago?TODAY[quote]CASTingSecond question of day: what is the len of @c?declare @c varchar(800)set @c = N'hello' + replicate('-',800)print len(@c)print @c Sorry - you were wrongCorrect answer: 800Explanation: The CAST to nvarchar(800) has a maximum 4000 character len. The CAST then to varchar(800) fits in that space, so the len is 800[/quote]2 days ago[quote]CASTingFirst question of day: what is the len of @c?declare @c varchar(8000)set @c = N'hello' + replicate('-',8000)print len(@c)print @cYou got it right!Correct answer: 4000Explanation: The CAST to NVARCHAR(4000) means that the maximum len is 4000, then the cast to varchar(8000) allows more characters, but the string is already truncated.[/quote]

RE: CASTing

John Mitchell-245523 — Thu, 29 May 2008 01:21:02 GMT

Sorry, I don't understand. [i]What[/i] CAST to nvarchar(800)? Is there a typo in the question?John

CASTing

Carlo Romagnano — Wed, 28 May 2008 22:41:09 GMT

Comments posted to this topic are about the item [B]CASTing[/B]