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What is the MySQL VARCHAR max size?

Keep in mind that MySQL has a maximum row size limit The internal representation of a MySQL table has a maximum row size limit of 65,535 bytes, not counting BLOB and TEXT types. BLOB and TEXT columns only contribute 9 to 12 bytes toward the row size limit because their contents are stored separately from … Read more

What is the difference between char, nchar, varchar, and nvarchar in SQL Server?

Just to clear up… or sum up… nchar and nvarchar can store Unicode characters. char and varchar cannot store Unicode characters. char and nchar are fixed-length which will reserve storage space for number of characters you specify even if you don’t use up all that space. varchar and nvarchar are variable-length which will only use … Read more

What are the main performance differences between varchar and nvarchar SQL Server data types?

Disk space is not the issue… but memory and performance will be. Double the page reads, double index size, strange LIKE and = constant behaviour etc Do you need to store Chinese etc script? Yes or no… And from MS BOL “Storage and Performance Effects of Unicode” Edit: Recent SO question highlighting how bad nvarchar … Read more

Difference between text and varchar (character varying)

There is no difference, under the hood it’s all varlena (variable length array). Check this article from Depesz: http://www.depesz.com/index.php/2010/03/02/charx-vs-varcharx-vs-varchar-vs-text/ A couple of highlights: To sum it all up: char(n) – takes too much space when dealing with values shorter than n (pads them to n), and can lead to subtle errors because of adding trailing … Read more

MySQL: Large VARCHAR vs. TEXT?

TEXT and BLOB may by stored off the table with the table just having a pointer to the location of the actual storage. Where it is stored depends on lots of things like data size, columns size, row_format, and MySQL version. VARCHAR is stored inline with the table. VARCHAR is faster when the size is … Read more

What is the difference between varchar and nvarchar?

An nvarchar column can store any Unicode data. A varchar column is restricted to an 8-bit codepage. Some people think that varchar should be used because it takes up less space. I believe this is not the correct answer. Codepage incompatabilities are a pain, and Unicode is the cure for codepage problems. With cheap disk … Read more