Set - 8

Question 31 :

Give the two types of tables involved in producing a star schema and the type of data they hold.

Answer :

Fact tables and dimension tables. A fact table contains measurements while dimension tables will contain data that will help describe the fact tables.

Question 32 :

What type of index should you use on a fact table?

Answer :

A Bitmap index.

Question 33 :

Give two examples of referential integrity constraints.

Answer :

A primary key and a foreign key.

Question 34 :

A table is classified as a parent table and you want to drop and re-create it. How would you do this without affecting the children tables?

Answer :

Disable the foreign key constraint to the parent, drop the table, re-create the table, enable the foreign key constraint.

Question 35 :

Explain the difference between ARCHIVELOG mode and NOARCHIVELOG mode and the benefits and disadvantages to each.

Answer :

ARCHIVELOG mode is a mode that you can put the database in for creating a backup of all transactions that have occurred in the database so that you can recover to any point in time. NOARCHIVELOG mode is basically the absence of ARCHIVELOG mode and has the disadvantage of not being able to recover to any point in time. NOARCHIVELOG mode does have the advantage of not having to write transactions to an archive log and thus increases the performance of the database slightly.