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itmasterw
Yak Posting Veteran
90 Posts |
 Posted - 2013-07-15 : 09:39:11
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| Hi,I have been asked to change a field that is varchar(4) from 5 -7 bytes. I am not sure what this is, I know it is varchar(4) rith now what would I have to chane it to to make it 7 bytes?thank you itmITM |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2013-07-15 : 09:53:32
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Either thisALTER TABLE dbo.Table1 ALTER COLUMN Col1 VARCHAR(7) or thisALTER TABLE dbo.Table1 ALTER COLUMN Col1 VARCHAR(7) NOT NULL
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itmasterw
Yak Posting Veteran
90 Posts |
Posted - 2013-07-15 : 10:08:39
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| So just so I understand, if they say go from 5-7 bytes, it just means to change the varchar to 7? There isn't formula that I have to use or anything?Thank you itmITM |
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James K
Master Smack Fu Yak Hacker
3873 Posts |
Posted - 2013-07-15 : 11:24:30
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| VARCHAR takes up as many spaces as there are characters plus one or two bytes for storing the length. So if you have VARCHAR(4), that takes up UP TO 5 bytes. I guess that is what they meant when they said change it from 5 to seven bytes - but I am guessing here. Ask them exactly what they mean by 5 bytes for a VARCHAR(4) column. And ask them what their goal is - do they want to store maximum of 6 characters, or maximum of 7 characters.In any case, what you will need to do is what Swepeso suggested. You may need to change the 7 to six perhaps. But ask questions first. |
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James K
Master Smack Fu Yak Hacker
3873 Posts |
Posted - 2013-07-15 : 12:17:31
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quote:
Originally posted by itmasterw
So just so I understand, if they say go from 5-7 bytes, it just means to change the varchar to 7? There isn't formula that I have to use or anything?Thank you itmITM
I see you edited the question after I posted my reply. But I am not sure what the edit was, so repeating what I posted earlier: there is no complex formula you have to use. You just need to get from them what they meant by "increase from 5 to 7" bytes, given that currently the column is VARCHAR(4). Depending on their answer, you would use Swepeso's query with a 6 or 7. |
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itmasterw
Yak Posting Veteran
90 Posts |
Posted - 2013-07-15 : 12:48:02
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Thanks, makes sence, I really appreaciate your help here guys.Thank you  ITM |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2013-07-15 : 13:24:27
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With VARCHAR(7) you can store up to 7 characters in that column.What is stored on disk and on page is different. Then you have to add NULL-pointers, 2 bytes for variable start pointer and 2 bytes for variable length information.
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bytes in a varchar