CHAR/VCHAR/NCHAR/NVCHAR/TEXT/NTEXT區別

Use varchar/nvarchar columns instead of text/ntext columns whenever possible.
Because SQL Server stores text/ntext columns on the Text/Image pages separately from the other data, stored on the Data pages, it can take more time to get the text/ntext values.


Use char/varchar columns instead of nchar/nvarchar if you do not need to store unicode data.
The char/varchar value uses only one byte to store one character, the nchar/nvarchar value uses two bytes to store one character, so the char/varchar columns use two times less space to store data in comparison with nchar/nvarchar columns.


Consider setting the 'text in row' SQL Server 2000 table's option.
The text, ntext, and image values are stored on the Text/Image pages, by default. This option specifies that small text, ntext, and image values will be placed on the Data pages with other data values in a data row. This can increase the speed of read and write operations and reduce the amount of space used to store small text, ntext, and image data values. You can set the 'text in row' table option by using the sp_tableoption stored procedure.