Database #

All tables or columns created by you should contain your plugin prefix and should be dropped after uninstallation. All columns except indexing fields for the DAL should be created in an own table to ensure migrations are fast executed on a larger data set.

In your own tables you have not prefixed all columns

Expensive migrations #

Expensive migrations should be avoided, as this migration could run into a timeout. An example migration could be

ALTER TABLE users
ADD COLUMN `count` SMALLINT(6) NOT NULL AFTER `lastname`;

The AFTER declaration makes that MySQL copies the entire table and relocates the columns. This can take very long, when the table is large and locks all operations on the table too. So the learning here is to avoid AFTER declaration.

Wildcard Selects #

Wildcard selects like:

SELECT table1.*, table2.*
FROM table1
INNER JOIN table2 ON(table2.id = table1.id)

Can be dangerous. When a plugin adds a similar column from table1 to table2 we will get an ambiguous MySQL error. So explicit selects are more secure.