Re: A guide about some topics of Associate Certification

Oscar Calderon wrote:
> Everybody have a nice day. Well, finally the place where i currently work paid me a chance to take the
> Associate Certification exam and i'm reviewing some topics, specifically the topics that the exam
> covers (some of them are easy to me like psql, which i use almost everyday) but i have doubt about 2
> of the topics and i don't know if i already have the knowledgement about those topics.
> 
> The topics are:
> 
> *    Postgres Data Dictionary: This is about information schema?

I am not sure because PostgreSQL does not use the term "data dictionary".
It *might* be this refers to the information_schema, but my bet is that
what is meant are the "system catalogs":
http://www.postgresql.org/docs/current/static/catalogs.html
Oracle uses the term "data dictionary" like that.

> *    Moving Data: This is about migration? Or about moving tablespaces in the file system?

I'm also not sure.
Maybe it is refering to
   ALTER TABLE table_name SET TABLESPACE new_tablespace
which will move the table to a different tablespace
(different from "ALTER DATABASE db_name SET TABLESPACE new_tablespace",
which will set the default for future tables).

Other things that move data around are commands like CLUSTER,
VACUUM FULL or forms of ALTER TABLE that rewrite the table,
but I don't know if I would headline them "moving data".

Yours,
Laurenz Albe