We have a customized Openbravo POS v2.2 running with a dozen workstations operating 24x7 a year around. The size of the database has grown to 10GB, and the performance started to degrade so we decided to archive old data and start fresh. According to the Openbravo POS administrative guide, we performed a DELETE operation on transaction data.

We have a dozen websites mostly running WordPress, and one Drupal website on Digital Ocean with a 1GB instance. The server was running flawlessly for 6 months, and then MySQL starts to crash every few days unexpectedly with the following error in the MySQL error log.

MySQL documentation states the following with respect to the "character set" and "collation" of the data storage in the database.

To change values of existing integer field (`table` is the table name, and "id" is the column name), you may use the following update SQL command:

We have been using the DirectAdmin control panel for a number of years, and each time we set up a server it is necessary to change the root password. By default, Direct Admin creates a MySql superuser called "da_admin" with a preassigned password, but we do not know what the root password is. Since we use both DirectAdmin and command-line to manage our server, it is essential that we have a proper MySQL root password assigned.

I've had a chance to with a Postgres database and came across a table with two primary keys. This intrigues me to look up a definition of primary and unique key. I always thought there would only be one primary key in a table, and the values have to be unique. But, what I saw in the PostgreSQL v8.1.23 was something otherwise. It allowed duplicate entries, and also allowed multiple primary keys in a table. Is this possible? Yes, it's called composite Primary Keys. Composite primary keys (multiple primary keys) makeup uniqueness in a table row -- which means composite primary keys work together to provide uniqueness.