Author Question: Explain denormalization, and why it may be appropriate to denormalize a set of tables. What will ... (Read 139 times)

MGLQZ · **on:** Jul 7, 2018

Explain denormalization, and why it may be appropriate to denormalize a set of tables.

What will be an ideal response?

Question 2

Explain the MySQL control-of-flow statements.

What will be an ideal response?

skipfourms123 · **Reply #1 on:** Jul 7, 2018

Answer to Question 1

Denormalization is the process of taking a normalized set of relations and converting them into a smaller set of relations that is in a lower normal form and thus vulnerable to a greater number of anomalies. While the fully normalized set of relations is more desirable from a theoretical perspective, it does have some disadvantages. The greater the number of relations in the database, the more work that is required by the database whenever data must be retrieved from multiple relations to reconstruct the users' view of the data. In some circumstances, the anomalies introduced by denormalizing a data model may be considered an acceptable cost for the performance improvement from reducing the overhead work performed by the database.

Answer to Question 2

The MySQL control-of-flow statements are used to direct which blocks of code are executed and in what order. Blocks of code can be labeled with block labels to identify them. The IF..THEN...ELSE..EN D IF structure is used to test conditions and execute code blocks based on the results, and also includes an IF...ELSEIF...END variant. The REPEAT and WHILE LOOP keywords are used to create repeating blocks of code. The LEAVE BlockLabel keywords are used to exit a block of code.