MySQL Bugs: #30530: Missprint at "10.1.4. Data Type Default Values"

Bug #30530	Missprint at "10.1.4. Data Type Default Values"
Submitted:	21 Aug 2007 7:26	Modified:	23 Aug 2007 8:04
Reporter:	Sveta Smirnova	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.0, 5.1, 4.1	OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
There is missprint:

 Implicit defaults are defined as follows:

    * For numeric types other than integer types declared *with the AUTO_INCREMENT attribute*, the default is 0. For an AUTO_INCREMENT column, the default value is the next value in the sequence. 

at http://dev.mysql.com/doc/refman/5.1/en/data-type-defaults.html

How to repeat:
Open provided link

Suggested fix:
Replace "declared with the AUTO_INCREMENT attribute" with "declared with the not AUTO_INCREMENT attribute"

It looks correct as written to me. What is the error?

Looks to me like a language problem. "Other than" implies a negation, so the following two statements mean the same: 

"For numeric types other than integer types declared *with the AUTO_INCREMENT attribute*, the default is 0."

"For numeric types that are not integer types declared *with the AUTO_INCREMENT attribute*, the default is 0."

Sveta, can you confirm that you'd consider the latter statement to be true?

Stefan,

you are right, this is language problem.

But when I found this is my missunderstanding I found this sentence still is incorrect:

mysql> create table t1(f1 float not null auto_increment primary key);
Query OK, 0 rows affected (0.10 sec)

mysql> insert into t1 values (), ();
Query OK, 2 rows affected (0.13 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from t1;
+----+
| f1 |
+----+
|  1 | 
|  2 | 
+----+
2 rows in set (0.00 sec)

Your example uses AUTO_INCREMENT with a non-integer type. AUTO_INCREMENT should be used only with integer types. (The server doesn't enforce this, unfortunately)

http://dev.mysql.com/doc/refman/5.0/en/create-table.html:

"Some attributes do not apply to all data types. AUTO_INCREMENT applies only to integer types."

Perhaps it should be considered a bug that the server does not complain about use of AUTO_INCREMENT with a non-integer type.

Sveta:

After discussing this with PeterG it seems sufficient for the Manual to say this:

"AUTO_INCREMENT applies only to integer types."

It could be considered a bug that the server doesn't disallow FLOAT or DOUBLE, but if you think so please file a new bug in the Server category.