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sql-serverencodingvarcharnvarchar
Leslie Jones
Leslie Jones

Reputation: 570

Is there dataloss from converting from varchar to nvarchar

I have a column in SQL Server that is varchar(MAX). The column has been populated with that data type. I now want to convert the column to nvarchar(MAX) to accept unicode characters.

Is there any data loss when I convert this column from varchar(MAX) to nvachhar(MAX)?

Upvotes: 3

Views: 2426

Answers (1)

Martin Smith
Martin Smith

Reputation: 453298

Every character that can be represented in varchar is also representable in nvarchar.

The only possible data loss issue would be if you have any varchar(max) values that are already greater than 1GB.

In most collations nvarchar uses 2 bytes per character and varchar uses 1 byte per character. Doubling the string length of a string > 1 GB would obviously take you over the 2GB limit.

Even then I would expect an error message rather than silent truncation but possibly it might silently fail under some settings such as ANSI_WARNINGS OFF.

Upvotes: 6

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