Overloading BINARY

Posted in: MySQL, Technical Track

“There are 10 types of people in the world — those who understand binary, and those who don’t.”

The term “binary” in MySQL has many different meanings. How many can you come up with? I have 6, but I am willing to believe there are more!

0) “Binary distribution” is the name for the package that contains a binary. Another use is “binary installation” but that’s pretty much the same usage pattern as “binary distribution”, so I won’t count “binary installation” as a separate usage.
1) “Server binary” or “client binary” is the actual program (mysqld, mysql).
2) “Binary format” is a compressed format. For example, DECIMAL is stored in a “binary format” — each group of nine digits is compressed into 4 bytes.
3) “Binary log” is the change log. You can argue that this is an extension of #3, because the binary log is a compressed log, but “binary log” is encountered ubiquitously in the MySQL world, and “binary format” is somewhat obscure knowledge.
4) “Binary CHARSET” – sets the collation to be case-insensitive. For instance, utf8_bin and latin1_bin are the binary collations for the utf8 and latin1 character sets, respectively.
5) “Binary string” – a byte string. This is also known as the BINARY data type. There is some kind of wit/pun in the fact that a number in binary is actually a “bit string”.

Any more I missed? There are over 1600 mentions of the word “binary” in the 5.0 manual!


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7 Comments. Leave new

I think there are over 11001000000 mentions of the word “binary” in the 5.0 manual!!! :-D


@safari — good point! For that matter, I actually have 1100 different ways the term “binary” is used.


There is the “binary” charset, and the different binary collations for normal charsets — You can set the charset of a varchar column to “binary” which will basically turn it into a varbinary column, otherwise every other charset as a *_bin collation type which you can use.

There is also the “binary” operator, equivalent to cast(nextvalue as binary), e.g. select binary ‘a’ = ‘A’


EDIT: …every other charset **has** a *_bin collation type…


@Nick — two more…wow!


There’s binary backup (also called “raw backup”), as opposed to logical backup.


Shlomi — neat, I usually call that “physical” backup…we’re up to 8 uses now!


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