Question

This question is from my database management system class.

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

2. What are general-purpose remarks columns, and why are they a problem?

Answer 1

Answer)

1) Denormalization is an optimization technique that is being used in the database wherein one can add the redundant data to either one or more tables wherein one can help in avoiding the joins in the relational database.

This is appropriate and important sometimes, as it acts as a strategy for enhancing the performance of the previously normalized database. This even enhances the read performance of the database at the expense of losing the write performance with the help of adding some of the redundant copies. There is a use of extra attributes in the table or creation of instances and the addition of new tables. This also minimizes the joins, modification time for the data, aggregate values, etc.

2) This is a common yet serious and difficult problem to solve where the columns like the comments or notes or the remark would have data which are important yet get stored in an inconsistent, and verbose manner.

It is a problem as it causes a problem when multiple values get stored in the same column. Example: Creation of new columns for every purpose and then extracting the data and storing it to new columns. These purposes are for all the content of the remark column.

It also creates a problem while the data for the foreign key are being stored in the remark column. Example: The foreign key value is obtained for the general-purpose remark column.

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