Hi all,
I'm from the DB2 world, new to MySQL, and would like to know about the Data Dictionary. From reading the documentation it looks like the Data Dictionary consists of tables that hold data about the MySQL databases and tables. Is that similar to the system catalog tables in DB2?

Thanks,

No... Not yet at leat but you can extract most of this information through DESCRIBE, SHOW TABLE STATUS, SHOW INDEX and other SHOW statements...

http://www.mysql.com/doc/en/SHOW.html

But you won't find that info in a table or a view... Not for now at least...

Okay, thanks bstjean. The show statements are helpful. But I guess I don't understand what the Data Dictionary tables are used for, if they don't hold the data about the tables/databases that I create.

MySQL has not data dictionary.

Hello ika,
In the MySQL Manual they talk about the Data Dictionary in:
http://www.mysql.com/doc/en/Table_and_index.html

Do you mean that there are no System Catalog tables?

What are the tables in database MySQL used for?
mysql> use mysql;
Database changed
mysql> show tables;
+-----------------+
| Tables_in_mysql |
+-----------------+
| columns_priv |
| db |
| func |
| host |
| tables_priv |
| user |
+-----------------+

When I create a new database a row isn't added to the db table.

The mysql database is used for permissions. An entry in the db table allows or denies specific permissions to certain users or hosts on the database level. The data dictionary is accessed only by using the SHOW and DESCRIBE syntax.