If you need to uninstall (eg disable) a recently installed plugin, perhaps because it has stopped your wordpress (WP) site from working then just use the following example.

Enter you domain control panel (cpanel, plesk, etc) and open phpMyAdmin (or any other database management system DBMS).

Select (click) the name of the database that corresponds to your WP installation; if you’re using CPanel then it usually takes the form of:

[cpanel_username][wdrp]

Once you have the correct Database table showing, then click on the table wp_options find the row active_plugins, click on the pencil icon to edit this value (if you’re using PHP-MyAdmin)

You will see something similar to the following, depending on the number and type of plugins you have installed:

a:3:{i:0;s:19:”akismet/akismet.php”;i:1;s:23:”wp-photo-album/wppa.php”;i:2;s:37:”wp-shopping-cart/wp-shopping-cart.php”;}

That entire array of code represents every active plugin on your site. Thus, to quickly disable all plugins without using the WP Admin area, highlight the entire block of code, cut it out, and paste it into a safe, offline text file. After removing the code, click the button to save your changes and that’s it.

All WordPress plugins are now deactivated (yet still installed, and with all plugin options intact). You can go through and reactivate all the plugins except the one that was causing you problems.

When creating or modify databases and their tables, it is essential that you understand how the tables relate, or how you want them to relate. Normalization is the process whereby tables are optimised via referential integrity to remove duplication, redundancy, and errors.

Two key ways to represent the fields, tables, and relationships is via ER (Entity-Relationship) Diagrams and Data Dictionaries. The ER Diagram is just that; a diagram (similar to a UML Class or Object diagram) which shows the tables and their data fields, as well as the relationship between tables.

The Data Dictionary is listing of the formatting  used to create you tables - eg relationships are viewed as Primary and Foreign keys etc. All the tables and their fields and formatting, as well as the Table Relationshops are also fully documented.

The ER Diagram is useful for taking a High Level view of the overall database including Relationships, where as the Data Dictionary is Essentially as it gives you key specific data - such as the field type, size, length, etc.