one character of data

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one character of data

VM-723206

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June 4, 2009 at 9:13 pm

#205835

Comments posted to this topic are about the item one character of data

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Eswin SSCrazy Eights Points: 8320 More actions · Answer 1

Eswin

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June 4, 2009 at 9:39 pm

#1005006

i think the ans is varchar(1).

Tanx 😀

ChiragNS One Orange Chip Points: 26137 More actions · Answer 2

Since it wont be empty or null Char(1) is the right answer to this question.

"Keep Trying"

MarkusB SSC-Dedicated Points: 37370 More actions · Answer 3

I've chosen for nchar(1) because it only says that the value won't be NULL or empty, but there's no limitation on the characters used. Also depending on your collation sometimes a character is covered by char but in another collation it's a nchar.

Try this:

CREATE TABLE #Chars(

c1 char(1) COLLATE SQL_Latin1_General_Cp850_BIN,

c2 nchar(1)COLLATE SQL_Latin1_General_Cp850_BIN,

c3 char(1)COLLATE SQL_Latin1_General_CP1_CI_AS,

c4 nchar(1)COLLATE SQL_Latin1_General_CP1_CI_AS)

INSERT INTO #chars

VALUES(CHAR(0128),CHAR(0128),CHAR(0128),CHAR(0128))

SELECT * FROM #chars

DROP TABLE #chars

As you can see the nchar value is consistent, while the char value depends on the collation.

[font="Verdana"]Markus Bohse[/font]

Edmund Ward SSChasing Mays Points: 620 More actions · Answer 4

I agree with MarkusB. I chose nchar(1). There's nothing in the question to suggest that this single character of data will be limited to single-byte chars. You set yourself up for trouble later if you don't anticipate all potential data.

Pyay Nyein Mr or Mrs. 500 Points: 565 More actions · Answer 5

"Either char(1) or varchar(1) may be used. Both would allocate 1 byte of space which would be used. "

doesn't varchar take extra 2 bytes for variant length? I think char(1) allocate 1 byte while varchar(1) allocate 3 bytes.

MarkusB SSC-Dedicated Points: 37370 More actions · Answer 6

Yes, varchar(1) is definitly wrong.

Also the question wasn't which datatype uses the least space, but what is best.

But how do you define best?

[font="Verdana"]Markus Bohse[/font]

Ben Leighton SSCommitted Points: 1838 More actions · Answer 7

Ben Leighton

SSCommitted

Points: 1838

June 5, 2009 at 3:10 am

#1005093

surely nchar(1)?

Rutger-969691 SSC Enthusiast Points: 122 More actions · Answer 8

I was thinking beyond US-ASCII, so I chose nchar(1) 🙂

Martin_Burton SSCommitted Points: 1850 More actions · Answer 9

The question is open to interpretatation, but i have to agree that is should be nchar(1)

Leo Hesen Ten Centuries Points: 1139 More actions · Answer 10

To be able to store every possible character in this variable it definitely has to be a nchar(1).

E.g. using 2-byte Unicode characters.

Leo

tony.sawyer Mr or Mrs. 500 Points: 559 More actions · Answer 11

I agree with many others that nchar(1) should be the correct answer because I am under the impression that varchars store an additional 2 bytes of data in the background to indicate the length of the data - so therefore Varchar(1) uses 3 bytes if it contains a byte of data and 2 bytes if the field was null or empty. I remember having discussions about the sensible minimum field length for varchar fields and when chars should be used instead to store least data. I could be wrong though...

Ashesh SSCommitted Points: 1961 More actions · Answer 12

I've chosen for nchar(1) because it only says that the value won't be NULL or empty, but there's no limitation on the characters used.

Thanks,
Ashesh

Dietmar Weickert SSCrazy Points: 2398 More actions · Answer 13

Hi,

The Online Manuals state it quite clearly:

http://msdn.microsoft.com/en-us/library/ms176089.aspx:

char [ ( n ) ]
Fixed-length, non-Unicode character data with a length of n bytes. n must be a value from 1 through 8,000. The storage size is n bytes. The ISO synonym for char is character.
varchar [ ( n | max ) ]
Variable-length, non-Unicode character data. n can be a value from 1 through 8,000. max indicates that the maximum storage size is 2^31-1 bytes. The storage size is the actual length of data entered + 2 bytes. The data entered can be 0 characters in length. The ISO synonyms for varchar are char varying or character varying.

http://msdn.microsoft.com/en-us/library/ms186939.aspx:

nchar [ ( n ) ]
Fixed-length Unicode character data of n characters. n must be a value from 1 through 4,000. The storage size is two times n bytes. The ISO synonyms for nchar are national char and national character.
nvarchar [ ( n | max ) ]
Variable-length Unicode character data. n can be a value from 1 through 4,000. max indicates that the maximum storage size is 2^31-1 bytes. The storage size, in bytes, is two times the number of characters entered + 2 bytes. The data entered can be 0 characters in length. The ISO synonyms for nvarchar are national char varying and national character varying.

So, depending on whether your horizon goes beyond the US or not, you may argue either for CHAR(1) or NCHAR(1), respectively.

Best regards,
Dietmar Weickert.

george sibbald SSC Guru Points: 104210 More actions · Answer 14

As what the characters might be was not specified, add a vote for nchar(1)

but so long as question generates debate...................

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