Storing and retrieving negative infinity in a MySQL database is accomplished by inserting an arbitrarily large negative number.  Negative infinity is handy when storing default values in a database.

The following SQL statement is an example of inserting negative infinity:

INSERT INTO test(negative_infinity) VALUES('-1e500');

Here is the test table:

CREATE TABLE test (
     negative_infinity DOUBLE NOT NULL
) ENGINE=INNODB character set utf8;

The value in the database is stored as the maximum negative value for the data type, double (-1.79769313486232e+308).

mysql> select * from test;
+------------------------+
| negative_infinity      |
+------------------------+
| -1.79769313486232e+308 |
+------------------------+
1 row in set (0.00 sec)

In Java, the Double contsant for max infinity, directly correlates to the value stored by MySQL.

Updating a block of rows in MySQL can be accompished by using the “limit” function:

update TABLE_NAME set COLUMN_NAME=VALUE limit MAX;

E.g.

update products set state=false limit 10;

Rebuilding an InnoDB table index is easy in MySQL 5.0. Simply type:

mysql> ALTER TABLE table_name ENGINE=InnoDB;

Warning: When dealing with large databases, this can place a lot of load on your DB.

An example of modifying a MySQL table to increase a VARCHAR column size:

alter table TABLE_NAME modify COLUMN_NAME VARCHAR(1024) NOT NULL;

This increases COLUMN_NAME to 1024 characters.

In MySQL 5.0 it is possible to drop unqiue constraints but, the syntax is not incredibly intuitive.

alter table TABLE_NAME drop index UNIQUE_CONSTRAINT_NAME;

Code Ghar provides a more thorough description.

Below are the steps to create a MySQL database and add a user

CREATE DATABASE testdb CHARACTER SET utf8 COLLATE utf8_general_ci;
GRANT ALL PRIVILEGES ON testdb.* TO 'testuser'@'127.0.0.1' IDENTIFIED BY 'sumthin' WITH GRANT OPTION;
GRANT ALL PRIVILEGES ON testdb.* TO 'testuser'@'localhost' IDENTIFIED BY 'sumthin' WITH GRANT OPTION;

All commands are executed in the MySQL console.