varchar(100) means each value in column can have maximum of 100 characters (ie Nevlon,Martin etc each of those values can be 100 char max)
varchar mean variable character. It implies that based of number of characters actually present, it will assume only the required space. ie for Nevlon it will take only size corresponding to 6 characters. In contrast, char datatypes takes the full size regardless of actual size of data. ie for Nevlon also it takes full 100 character size and fills the rest with spaces. You can check that using below code.
SELECT DATALENGTH(varcharval),DATALENGTH(charval)
FROM
(
SELECT CAST('Nevlon' AS varchar(100)) AS varcharval,CAST('Nevlon' AS char(100)) AS charval
)t
The varchar field will only return size corresponding to 6 characters present whereas char will return size corresponding to entire 100 characters
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data types related question
Posted - 02/17/2013 : 00:44:26
